# Deep Sky Astrophotography (Gear Discussion)



## jrista (Dec 5, 2013)

There is already a stars above thread, but that one seems to be about wide field astrophotography. I've been taking a bunch of photos of the comets flying through the sky lately. Only ones I was able to get a decent shot of was Lovejoy R1 (see the Comets thread). 

I discovered an intriguing new technique for stacking very short deep sky frames in photoshop, one which nearly eliminates noise without affecting detail. I've been trying to stack short (i.e. 1-2 second) frames of the Orion nebula for a while, never with satisfactory results...always still too much noise. This new technique resulted in my first fairly decent photo:








*Body:* Canon EOS 7D
*Lens:* Canon EF 100mm f/2.8
*Exposure:* 1s f/2.8 ISO 1600
*Frames:* 30

I stacked the frames in the following way:

[list type=decimal]
[*]Import as Layers to Photoshop fron LR
[*]Align all layers (did it manually, auto-align freaked out for some reason)
[*]Select first 5 layers, Layers->Smart Objects->Create
[*]Set stacking mode to mean, Layers->Smart Objects->Stack Mode->Mean
[*]Repeat 3-4 for each group of 5
[*]Rasterize each smart object
[*]Set opacity mode to (from bottom most light frame): 100%, 83%, 66%, 50%, 33%, 16%
[*]Set blending mode to Screen for all light frames
[*]Add Levels adjustment layer and correct black point, white point, and gray point to bring out most detail
[*]Tweak color, levels, curves, etc. to taste
[/list]


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## 49616E (Dec 5, 2013)

*Re: Deep Sky Astrophotography*

That is an interesting work flow for it, I will have to check that out. 

Most of the time I see people going in to 32-bit mode then using linear dodge (add). You can use the exposure adjustment towards the bottom of the window while you are stacking. This way should be much easier than the method you outlined since you just have them all stacked and you don't need to go through separate groups, just linear dodge add them all. After you do that you convert it back to 16 or 8 bit mode and adjust the exposure during the convert, I usually just use the exposure/gamma conversion.

Also a tip for aligning the layers, I typically use difference for the layers compared to one "master" layer. Seems to allow for more precision, especially while doing rotation to correct for field rotation unless you are using an equatorial mount. 

I will attach one of my recent ones of good ole' M42. Let me know if you have any questions about it.


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## jrista (Dec 5, 2013)

*Re: Deep Sky Astrophotography*



49616E said:


> That is an interesting work flow for it, I will have to check that out.
> 
> Most of the time I see people going in to 32-bit mode then using linear dodge (add). You can use the exposure adjustment towards the bottom of the window while you are stacking. This way should be much easier than the method you outlined since you just have them all stacked and you don't need to go through separate groups, just linear dodge add them all. After you do that you convert it back to 16 or 8 bit mode and adjust the exposure during the convert, I usually just use the exposure/gamma conversion.
> 
> ...



Thanks for the 32bit linear dodge tip. I'll have to give that a try (although I've used linear dodge in the past, with 16bit int, and the results were still far noiser than I got here.) 

As for the layer alignment, I actually do use the difference technique if I do it manually. I'm bummed Photoshop's registration feature doesn't work...it does some weird stuff, despite the fact that all the photos were pretty much identical except the shift of the nebula across the frame. The photo above is a 100% crop, so it was rather tiny in the full frame...maybe that's why. Without a tracking mount, I don't have the ability to expose long enough at a longer focal length. 

Your photo has the benefit of being much larger in the frame. I have a telescope with an equatorial tracking mount on order, along with a t-adapter and t-ring, so I should be able to do much better in the future. The technique I outlined above is just for those who don't have the benefit of tracking their subject, or keeping it large in the frame without trailing.


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## 49616E (Dec 5, 2013)

*Re: Deep Sky Astrophotography*

Yeah, the linear dodge won't work at all really in 16bit mode. I hope it works out for you! I have used it in similar situations as with the focal length and no tracking as you did with great results.

As for photoshop's alignment for astrophotography.... He he. I have never had it work, even with the picture I provided I had to do it manually. It seems that the way registax does it is better where you pick alignment points, although I have not used it much yet.

My exposure times for that picture were 2 seconds, that is about all I could do at the time before field rotation started to become much more obvious (I just used an alt/az goto dobsonion). It is with a 50D at ISO 3200, so the original frames were pretty noisy. I want to say I used about 9 frames for it though. But yes, as you observed, it definitely helps to fill up that frame.

Should be a bunch of fun when you get that EQ mount!


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## jrista (Dec 5, 2013)

*Re: Deep Sky Astrophotography*



49616E said:


> Yeah, the linear dodge won't work at all really in 16bit mode. I hope it works out for you! I have used it in similar situations as with the focal length and no tracking as you did with great results.
> 
> As for photoshop's alignment for astrophotography.... He he. I have never had it work, even with the picture I provided I had to do it manually. It seems that the way registax does it is better where you pick alignment points, although I have not used it much yet.



Out of curiosity, have you ever tried DeepSkyStacker? Currently, I would have to say DSS is my favorite stacking tool. At least, it's registration process and denoising process (which can factor in dark, bias, flat, and flat bias frames) is one of the best. The only problem I have with it is tweaking the final result, which can be a real pain in the butt. Still, if you take a lower-contrast result, and do all the final work in Photoshop, the results can be quite good. 

I am going to run all these photos I took through DSS, it's just a bit more time consuming (it's registration and stacking process can take a VERY long time, depending on how much you throw at it). I also wanted to play around with the Smart Object stacking modes to see what they could do. I have to say, median and mean stacking does a phenomenal job with noise removal. I bet you could do still life/landscape photography with multiple frames on a tripod at ISO 100, and stack them with photoshops stack merge feature to produce entirely noiseless images (and maybe even mitigate banding in the shadows.) 



49616E said:


> My exposure times for that picture were 2 seconds, that is about all I could do at the time before field rotation started to become much more obvious (I just used an alt/az goto dobsonion). It is with a 50D at ISO 3200, so the original frames were pretty noisy. I want to say I used about 9 frames for it though. But yes, as you observed, it definitely helps to fill up that frame.
> 
> Should be a bunch of fun when you get that EQ mount!



Not bad at all for 9x2s frames...of course, with the subject larger in the frame, you gathered a lot more light, but still, pretty nice results! Can't wait to get my hands on a proper tracking mount... 8)

I was in the market for the biggest Celestron NexStar (I think the 8") for a while until I realized it only came with the alt/az mount. Then I started saving for the Celestron EdgeHD 11", however finances have become extremely tight. So I just dropped some cash on the Celestron AstroTracker 114 EQ w/ motor drive. It is a super basic telescope, almost your bottom rung entry level. But, it has a tracking equitorial mount, for damn cheap, and some of the astrophoto stacks I've seen made with it were pretty decent (and all from total beginners). I bet I could slap together a little guidescope setup with a webcam and my Surface Pro tablet, and get some pretty good results. The telescope tube also has a standard tripod mount screw attached to it, which allows you to screw on a DSLR camera for wide field tracking, too. Whole setup (with the t-adapter/ring) wasn't even $250 on sale (http://www.telescopes.com/telescopes/reflecting-telescopes/celestronastromaster114eqreflector.cfm), which is a pretty good deal, and I figure it will hold me over until I can afford the EdgeHD 11" w/ CGEM DX mount (which probably won't happen until the end of the year next year at the earliest.)


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## Mr Bean (Dec 5, 2013)

*Re: Deep Sky Astrophotography*

Nice pic's folks.

jrista, regarding your technique, I like the simpleness of it (not using any tracking), to achieve a great result. The last time I took a picture of M42, I had gas sensitized film, and the exposure was 1.5hrs 

I'll give this approach a go in the next month, as Orion steadily rises.


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## 49616E (Dec 6, 2013)

*Re: Deep Sky Astrophotography*



jrista said:


> Out of curiosity, have you ever tried DeepSkyStacker? Currently, I would have to say DSS is my favorite stacking tool. At least, it's registration process and denoising process (which can factor in dark, bias, flat, and flat bias frames) is one of the best. The only problem I have with it is tweaking the final result, which can be a real pain in the butt. Still, if you take a lower-contrast result, and do all the final work in Photoshop, the results can be quite good.



Nope, I have not tried DeepSkyStacker yet although I look forward to at some point. Thanks for the suggestion!



jrista said:


> I am going to run all these photos I took through DSS, it's just a bit more time consuming (it's registration and stacking process can take a VERY long time, depending on how much you throw at it). I also wanted to play around with the Smart Object stacking modes to see what they could do. I have to say, median and mean stacking does a phenomenal job with noise removal. I bet you could do still life/landscape photography with multiple frames on a tripod at ISO 100, and stack them with photoshops stack merge feature to produce entirely noiseless images (and maybe even mitigate banding in the shadows.)



Yes, I have done that very thing with still life stuff (with the linear dodge add method), it works quite well in my opinion, especially if you are going to do a large print. At ISO 100 you only need about two or three frames and you get an extremely clean image indeed!




jrista said:


> Not bad at all for 9x2s frames...of course, with the subject larger in the frame, you gathered a lot more light, but still, pretty nice results! Can't wait to get my hands on a proper tracking mount... 8)
> 
> I was in the market for the biggest Celestron NexStar (I think the 8") for a while until I realized it only came with the alt/az mount. Then I started saving for the Celestron EdgeHD 11", however finances have become extremely tight. So I just dropped some cash on the Celestron AstroTracker 114 EQ w/ motor drive. It is a super basic telescope, almost your bottom rung entry level. But, it has a tracking equitorial mount, for damn cheap, and some of the astrophoto stacks I've seen made with it were pretty decent (and all from total beginners). I bet I could slap together a little guidescope setup with a webcam and my Surface Pro tablet, and get some pretty good results. The telescope tube also has a standard tripod mount screw attached to it, which allows you to screw on a DSLR camera for wide field tracking, too. Whole setup (with the t-adapter/ring) wasn't even $250 on sale (http://www.telescopes.com/telescopes/reflecting-telescopes/celestronastromaster114eqreflector.cfm), which is a pretty good deal, and I figure it will hold me over until I can afford the EdgeHD 11" w/ CGEM DX mount (which probably won't happen until the end of the year next year at the earliest.)



Yeah the EdgeHD 11" would be very nice to have. Nice deal on the Astrotracker, I know a few people that have imaged with it, definitely very capable for that price. Any tracking at all is a huge improvement over a regular tripod. Should be able to play around with that long enough and get used to it till you get the EdgeHD. Maybe even learn some handy things along the way. 

So although it is not a perfect experiment, I took some shots before it was perfectly dark. I tried the linear dodge add method and the mean method as you have outlined. I think they pretty much end up doing the same thing although you have different results to do your final adjustments with. I tried to do minor post production and have them appear as similar as possible although I did not do that great of a job and did not really focus on making them pretty or anything, but I think it gives the general idea. With enough tweaking I think they would be pretty much identical. I will say that I find the linear dodge work flow a little easier than all the switching around with smart layers and stacks. after alignment you just select all the layers and change it to linear dodge add and then convert to to 16bit. But that may just be my personal preference. I am glad I tried the mean method though, it is always neat to see the different ways of doing something

The first one is linear dodge and the second is the mean.

Camera: 50D Full Spectrum modified
Exposure: 2sec
ISO: 3200
Focal Length: 400mm
F:5.6
Stack of 20
100%crops


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## jrista (Dec 7, 2013)

*Re: Deep Sky Astrophotography*



49616E said:


> Yeah the EdgeHD 11" would be very nice to have. Nice deal on the Astrotracker, I know a few people that have imaged with it, definitely very capable for that price. Any tracking at all is a huge improvement over a regular tripod. Should be able to play around with that long enough and get used to it till you get the EdgeHD. Maybe even learn some handy things along the way.



Aye. Hands on experience is a necessity at some point. I had hoped to start getting hands on tracking experience months ago, but alas, things changed. And as you say, any tracking is a huge plus. I am also curious if I'll be able to figure out a way to mount my 600mm lens and camera directly to the equatorial mount. I am not sure if it will take the weight, which would be around 12 pounds I guess. With a 2x TC, I have a 1200mm "telescope", and with both TCs it is 1680mm. That is pretty decent for planetary photography!



49616E said:


> So although it is not a perfect experiment, I took some shots before it was perfectly dark. I tried the linear dodge add method and the mean method as you have outlined. I think they pretty much end up doing the same thing although you have different results to do your final adjustments with. I tried to do minor post production and have them appear as similar as possible although I did not do that great of a job and did not really focus on making them pretty or anything, but I think it gives the general idea. With enough tweaking I think they would be pretty much identical. I will say that I find the linear dodge work flow a little easier than all the switching around with smart layers and stacks. after alignment you just select all the layers and change it to linear dodge add and then convert to to 16bit. But that may just be my personal preference. I am glad I tried the mean method though, it is always neat to see the different ways of doing something
> 
> The first one is linear dodge and the second is the mean.
> 
> ...



Thanks for the test. Very interesting results. From a noise standpoint, they do indeed look identical. From a color standpoint, colors are a touch richer with the Median method, and stars are just a little softer, too. 

The Linear Dodge Add method definitely sounds simpler. I'm going to give that a try now, with the previous photo I posted above, and see how things look. I think I may also try photographing the nebula with my 600mm lens for 1-2 seconds and stack em, see how things turn out. I figure downsampling for web should take care of a lot of the trailing.


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## jrista (Dec 7, 2013)

*Re: Deep Sky Astrophotography*

@49616E: Any chance you could outline your specific LDA method? I converted a copy of my original working file (just the aligned raw images, no other adjustments) to 32 bit, and set all 30 frames to Linear Dodge Add. The results were far noisier than the mean/median approach, and I seem to be having problems tuning the exposure/levels.

Thanks.



Here are my results, using the various methods I know. 

1. The original method I used to use was something I found years ago on a basic astro photography stating tutorial. I used this to a degree in my original post, I call it the gradient ramp method, where you successively increase opacity of each layer from the top to the bottom of the layers list. It is simple, moderately effective, but breaks down when you start to tweak the results with adjustment layers and whatnot.

2. The 32-bit float (HDR) LDA (Linear Dodge Add). First time I've tried this with 32-bit. With 16-bit, you can't stack too many frames before the whole image just becomes white. As such, you can't really remove a lot of noise. Seems moving to 32-bit improves your options...but I may be doing something wrong, as the results (without any other tweaks) seem to be the worst of the three.

3. The median method, where you stack into a smart object then set the stacking mode to Median or Mean. PHENOMENAL noise reduction, especially when you stack a lot of frames. It can almost entirely eliminate noise. Your editing latitude goes through the roof. If you stack too many frames into a smart object, you'll start to lose color fidelity (in the example below, all 30 frames were stacked in one smart object, vs. my original post, where I created batches that were stacked then gradient ramped.) 



*Original Light Frame (1 frame to show noise):*





*Gradient Ramp Method (30 frames):*





*Linear Dodge Add Method (30 frames):*





*Median/Mean Method (30 frames):*





I tweaked the above 30-frame stacks using the LDA and Mean methods. Assuming I did the LDA method correctly, once I started dropping on adjustment layers, there was a marked difference in editing latitude between LDA and Mean. Mean had far more _before_ noise started to exhibit. It was more forgiving and flexible, allowing fine tuning to tighter ranges of tones, without resulting in harsh gradients or transitions. I was able to maintain the black point better with Median than LDA (which ended up a little more red, but pushing it too far resulted in more noise.) Median preserved more subtle and dimmer tones in the outer regions of the nebula, where as LDA clipped more of the outer regions to the noise floor.

(Again, this is assuming I used the LDA method correctly):

*Fine Tuned LDA:*





*Fine Tuned Median:*


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## jrista (Dec 11, 2013)

*Re: Deep Sky Astrophotography*

Tried another stack tonight. This time, I used an 840mm f/5.6 lens to capture 50x0.6s shots at ISO 4000. Stacked them in a hybrid manner:

[list type=decimal]
[*]Align in Photoshop (difference method)
[*]Convert batches of 10 layers into Smart Objects (5x smart objects total)
[*]Set Stacking Mode for each smart object to Median
[*]Set blending mode for top 4 smart objects to Linear Dodge Add
[*]Ramped the opacity for each smart object: 100%, 85%, 70%, 55%, 40%
[*]Applied adjustment layers to bring out dust detail, tweak color, etc.
[*]Flattened, unsharp masked, cropped, resized, exported.
[/list]

Stacking 10 frames into smart objects with median blending resulted in amazingly low noise. Tweaking color and whatnot brought some of that noise back out, but it was still far lower than I've ever had with non-tracked deep sky astro before.


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## Rienzphotoz (Dec 14, 2013)

*Re: Deep Sky Astrophotography*



jrista said:


> Tried another stack tonight. This time, I used an 840mm f/5.6 lens to capture 50x0.6s shots at ISO 4000. Stacked them in a hybrid manner:
> 
> [list type=decimal]
> [*]Align in Photoshop (difference method)
> ...


AWESOME! ... I've never tried Astrophotography before, but your images have given me lots of inspiration ... I plan on trying it within the next 2 or 3 weeks during my vacation and will also try out your editing method. Thanks for sharing.


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## jrista (Dec 15, 2013)

*Re: Deep Sky Astrophotography*



Rienzphotoz said:


> jrista said:
> 
> 
> > Tried another stack tonight. This time, I used an 840mm f/5.6 lens to capture 50x0.6s shots at ISO 4000. Stacked them in a hybrid manner:
> ...



It is really fun! Without a tracking mount, it is a holy hell of a LOT of work, though. The technique I used above is the only one that actually made non-tracking deep sky astrophotography worth it for me, as it actually brings out some detail from images that almost look entirely black before processing...but it takes a LOT of images. 

I purchased a really basic Newtonian reflector with simple motorized R.A. tracking. It isn't perfect, and over time there is still drift in declination, but I am hoping, assuming I can get it polar aligned right and figure out the correct slew speed, that it will get me some better light frames to work with, and lighten my workload. (Ironically, it doesn't even gather as much light as my 600mm f/4 lens!!  The telescope has a 114mm aperture, where as the 600/4 has a 150mm aperture. The real benefit of the telescope is its tracking...hopefully I can figure it out and get it working right. Well, either way...I'll be posting something here soon enough. Maybe I'll be able to get the horse head nebula!! )


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## jrista (Jan 2, 2014)

*Re: Deep Sky Astrophotography*

Did some more astrophotography last night. Worked on some wide field stuff, using my 100mm f/2.8 macro lens. Managed to get some decent results with stacking, but the 7D's low SNR is really killing me. Here is the axis of nebula in Orion:






From the bottom, you have M42 (Orion Nebula), M43 (De Mairan's Nebula), IC434 (Emission Nebula behind Horse Head), NGC 2024 (Flame Nebula) and M78 (follow the axis of orion, horse head, and flame nebulas up near the top edge, small smudge is a reflection nebula.) This is a stack of 30 frames, each 8 seconds long, ISO 3200. 

(NOTE: The noise of the 7D, even after median stacking, is simply too great to eliminate with such short exposures and low signal. I pushed the exposure around as much as I could without making the noise overly apparent, but blah...if you see a lot of it, your screen is to bright!!  Hope a 5D III (or better, a decent telescope and a peltier-cooled CCD astro camera) finds it's way into my hands sometime in the near future. )


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## scyrene (Jan 2, 2014)

*Re: Deep Sky Astrophotography*

I dunno if my experience is relevant, but I held out for as long as I could before I got a tracking mount. You can do good stuff with short exposures if you go through the proper motions of dark and flat frames, and stacking a lot. Dark skies/astro filters probably make the most difference beyond that. I do all my aligning and stacking by hand in Gimp (I'm not sure any of the good free astro stack/align software is available for Macs, but anyhow that's what I'm used to now). Having said that, a tracking mount can push things further than anything. Exposure times of tens of seconds up to minutes can be transformative.


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## jrista (Jan 3, 2014)

*Re: Deep Sky Astrophotography*

Reprocessed a few times with DeepSkyStacker. Tweaking the final result is a real PITA, but when you figure out how to do it right, the results are much better:








scyrene said:


> I dunno if my experience is relevant, but I held out for as long as I could before I got a tracking mount. You can do good stuff with short exposures if you go through the proper motions of dark and flat frames, and stacking a lot. Dark skies/astro filters probably make the most difference beyond that. I do all my aligning and stacking by hand in Gimp (I'm not sure any of the good free astro stack/align software is available for Macs, but anyhow that's what I'm used to now). Having said that, a tracking mount can push things further than anything.



You can extract a certain degree of quality from non-tracked stacking, but there is a limit. With short exposures, you have a very low signal strength. While you can improve SNR with stacking, you can't improve the actual image signal strength beyond a certain point, so you can never get the nice fine detail that a long exposure gets you. I've spent about two months now trying...and the shot above is about as good as I think I'll be able to do without tracking (or exceptionally dark skies, which are really rare and hard to find.) 

I have done a fair amount of manual stacking in Photoshop, and the results can be quite good. Stacking software, especially the more complicated versions like DSS, Nebulosity, etc. are much more capable, but they have a high learning curve, and often their toolsets are difficult to use. I have avoided DSS up till now, but I just spent the bulk of the day working on the shot above, and I think I finally have it figured out. It's a bit noisy (it got much too cold last night, and I packed it in before I took dark frames and bias frames), but that can easily be delt with. 



scyrene said:


> Exposure times of tens of seconds up to minutes can be transformative.



Indeed! I can't wait to get my hands on the Celestron EdgeHD 11" CGEM DX. I had my eyes on a 5D III for my next photography, but I think I'm going to move the telescope to the top of my list. I am curious to see how the 7D II turns out, and for astrophotography, no DSLR will really do what I want, so I'm planning on getting a monochrome CCD with the biggest pixels I can find (probably around 9µm to 9.5µm, or perhaps 5µm with the option to 2x2 bin) an dual-stage peltier cooling (which gets you up to around 77% Q.E.) I'll then be able to filter Ha, Hb, Luma, R, G, B, and any other bands independently, and blend them in post for very high detailed, full-color wide band images.


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## Don Haines (Jan 3, 2014)

*Re: Deep Sky Astrophotography*



jrista said:


> Reprocessed a few times with DeepSkyStacker. Tweaking the final result is a real PITA, but when you figure out how to do it right, the results are much better:
> 
> 
> 
> ...


It's -33C here tonight.... I'm not terribly worried about peltier cooling  

I have an 8" Celestron with a tracking mount.... I have tried the 60D on it, but there is WAY to much noise... My friend's 5D2 work's much better, but it is an hour's drive away and that rules it out most of the time...

I have been thinking of getting one of these.... http://focusscientific.com/osCommerce/catalog/product_info.php/cPath/94_47/products_id/649
or
http://focusscientific.com/osCommerce/catalog/product_info.php/cPath/94_47/products_id/650


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## jrista (Jan 3, 2014)

*Re: Deep Sky Astrophotography*



Don Haines said:


> jrista said:
> 
> 
> > Reprocessed a few times with DeepSkyStacker. Tweaking the final result is a real PITA, but when you figure out how to do it right, the results are much better:
> ...



If you have a tracking mount, you should be able to do worlds better than I can with the 60D. You could expose for minutes, which would create a very strong signal. You could then stack, and median averaging or something like Kappa-Sigma clipping in DSS would clean up the noise right away. I think your selling your 60D a bit short. My shots are about as good as I can do with a 7D right now because I lack a tracking mount...if I had one, I guarantee you I'd be making MUCH better shots. 

There is no question that a FF sensor would do better, but the problem with the 7D (or any Canon 18mp APS-C body) with non-tracked shots is the fact that they have pitifully low signal and crappy read noise. If you can make the signal strength 100 - 1000 times more powerful, then even Canon's 18mp APS-C bodies will do very well (I've seen a lot of exceptional astrophotography from the lowly rebel series when they are used on tracking mounts.) You should give your 60D another try, and do something like 30x10 minute exposures (five full hours of tracked exposure)...I would bet the results would blow anything I've posted here WAY out of the water.




Don Haines said:


> I have been thinking of getting one of these.... http://focusscientific.com/osCommerce/catalog/product_info.php/cPath/94_47/products_id/649
> or
> http://focusscientific.com/osCommerce/catalog/product_info.php/cPath/94_47/products_id/650



For a first astrophotography camera, I suspect I'll get the Celestron Nightscape CCD. I've seen some truly amazing images made from it, and it isn't too terribly pricey (around $1500 most of the time.) 

The cameras I really want in the long run, though, are these beauties:

QHY11 FF Monochrome

Full frame, 11mp, huge 9µm pixels, monochrome, FWC ~= 6D or 5D III (around 60ke-) with Kodak CCD, read noise ~13e-.

QHY23 Monochrome

APS-C, 9mp, small 3.69µm pixels, supports 2x2 and 4x4 binning (7.38µm and 14.76µm effective pixel sizes), highest Q.E. on the market for an astro CCD @ 77% (visible green, 60% Ha & 70% Violet/Ultraviolet), FWC ~= 7D/60D/Canon 18mp APS-C (around 20ke-) with Sony CCD, read noise ~5e-. 

I figure I would want both, depending on the thing I am imaging and how finely I want to delineate detail. Probably years away from getting either...the FF one is $4000, and the cropped one is $3000.  I am sure the Celestron Nightscape will do in the interim. The one thing that seems strange to me is the readout rate of most CCD astro cameras. The often list the readout rate at Xmegapixels per second, and usually that X is significantly lower than the total megapixels on the sensor. So, for an 11mp sensor with a 1mp/s readout rate, it would take a full 11 seconds to read out the whole sensor. For the 9mp sensor, it would take over 7 seconds to read out the whole sensor. I suspect that has to do with maintaining low read noise...but it was still surprising.


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## scyrene (Jan 4, 2014)

*Re: Deep Sky Astrophotography*

No doubt non-tracked stacks can't compete, but it depends what your hoping for. I was coming from non-tracked single shots, and every step forward was enough to encourage me further.

I've gone down a different route. I got a telescope, but found it unwieldy and counterintuitive. So now I have a small tracking mount designed for cameras, and the telescope is gathering dust. The downsides are inability to dial in locations in the sky (so I basically have to use trial and error for objects fainter than I can see), and an upper limit to exposure time (it's not as stable or accurate as a good tracking telescope mount, but it's enough for now and a lot cheaper).

I found, aside from tracking, the biggest improvements were made by adding an astronomical filter (I currently use a UHC filter that clips into the camera body - Astronomik do a range, APS-C only), and using wider aperture lenses. Although shooting wide open adds some optical problems, the extra light gathering at f/1.2 versus f/2.8 is stunning for the night sky.

The biggest problem is still the weather! Cloud-free, low wind nights below the dew point are rare indeed in these parts.


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## weixing (Jan 4, 2014)

*Re: Deep Sky Astrophotography*

Hi,
It's a long time since I last do some Astrophotography due to the unpredictable weather... 



scyrene said:


> I found, aside from tracking, the biggest improvements were made by adding an astronomical filter (I currently use a UHC filter that clips into the camera body - Astronomik do a range, APS-C only), and using wider aperture lenses. Although shooting wide open adds some optical problems, the extra light gathering at f/1.2 versus f/2.8 is stunning for the night sky.


 Any problem when you use those fast lens with the Astronomik filters?? I thought they are design for f3.8 to f15...

By the way, now they have clip on filters for Canon 5D and 6D full frame camera, but I think you had to lock the mirror in up position to install the filters, so might not be that useful if you need the viewfinder to aim.

Have a nice day.


----------



## scyrene (Jan 4, 2014)

*Re: Deep Sky Astrophotography*



weixing said:


> Any problem when you use those fast lens with the Astronomik filters?? I thought they are design for f3.8 to f15...
> 
> By the way, now they have clip on filters for Canon 5D and 6D full frame camera, but I think you had to lock the mirror in up position to install the filters, so might not be that useful if you need the viewfinder to aim.



Is that right? I'll have to see - using the 5DIII would improve things a lot. One thing that's relevant in any case is the Astronomik EOS clip filters (for 1.6 crop bodies) actually fit into the super telephoto lens rear filter holder (on my 500 II at least). Sadly my tracking mount can't handle the weight of that lens and body combination, so I've never made much use of it - but it's worth knowing.

As for aperture, I suspect it's the reason I get a lot of halos around stars. They are, as you say, rated for medium to narrow apertures (by lens standards). With the UHC filter, many stars get bright magenta halos, which can be a pain to remove if your main subject is a red/pink nebula. Nonetheless, other than that, I've found no problems, and a tradeoff worth making in my experience.


----------



## lol (Jan 4, 2014)

*Re: Deep Sky Astrophotography*

I had a chat with Astronomik in the past about their narrowband filters and fast lenses. I think the e-mails are on my work account so I can't find it right now. Although their website rates them as usable from f/2.8, they said f/2.0 was ok. Any benefit from going even faster will reduce.

I did a lot of my early attempts with the 135L wide open. Note the lens is rather horrible for wideband imaging as the red focus is some way off that of green/blue. It is fine for narrowband.

If you go for only light pollution filters like the CLS, that should be less affected by extreme speed but I haven't tried it.

And finally, I didn't realised they did full frame clip filters now! Shall have to have a look. Requiring mirror lock up isn't a big deal. People like using USB connection to help with focusing so you see what the sensor sees. My biggest problem now is, do I really want to modify my 5D2?... probaby not, I've not gathered a single night sky photon this winter. Must stop being lazy! Not a great hobby if you don't like the cold.

Edit: here's one of my early attempts at Andromeda galaxy with the 135L at f/2, CLS filter on 600D (unmodified). 100% crop, processed. I have got a bit better since then...


----------



## Quasimodo (Jan 4, 2014)

*Re: Deep Sky Astrophotography*

This is imho the most inspirational thread I have read in this forum for quite a while!

I have never tried astrophoto myself (except when I was lucky to borrow the 800/5.6 with a 2xIII TC to take picture of the moon, but that would hardly count as the moon is very bright so the exposure time is very short). 

I have been reading this whole thread on my ipad retina, and it has quite good resolution. However, due to the restrictions on image size here in CR, I would have loved to see full resolution images of your beautiful pictures if you guys have posted them somewhere else?


----------



## scyrene (Jan 4, 2014)

*Re: Deep Sky Astrophotography*



lol said:


> Edit: here's one of my early attempts at Andromeda galaxy with the 135L at f/2, CLS filter on 600D (unmodified). 100% crop, processed. I have got a bit better since then...



I'd have been very happy with that! Andromeda is a target I've struggled with. Partly because it's hard to locate (no very bright nearby stars) and partly my filter seems to bring out hydrogen emission nebulae much better than galaxies or reflection nebulae (e.g. the Pleiades).

Incidentally, the 135L is a lens I've considered as my next step for this work. Would you recommend it? The 100L macro has done pretty good service so far, but I'd love more reach (and as I say, the 500L II is too heavy for my tracking mount).


----------



## lion rock (Jan 4, 2014)

*Re: Deep Sky Astrophotography*

LOL,
What a fantastic image, I would think it came out of KECK in Hawaii!
Hats off to you. Please show more, with a bit of instructions to the rest of us!
Thanks.
-r


----------



## jrista (Jan 5, 2014)

*Re: Deep Sky Astrophotography*



scyrene said:


> weixing said:
> 
> 
> > Any problem when you use those fast lens with the Astronomik filters?? I thought they are design for f3.8 to f15...
> ...



Hmm! I'll have to check out Astronomik's filters for the supertelephoto lenses. I have the 600/4 L II, which is basically like a good Apochromatic refractor. I have my eye on the Celestron CGEM DX mount, which is about $1200 alone, and it should be able to hold my lens and camera quite easily. Having a light pollution filter would make it a lot easier for me to do some deep sky astrophotography without having to find time to drive an hour or so out of town to find clean dark skies. Thanks for the tip! 



scyrene said:


> lol said:
> 
> 
> > Edit: here's one of my early attempts at Andromeda galaxy with the 135L at f/2, CLS filter on 600D (unmodified). 100% crop, processed. I have got a bit better since then...
> ...



Ditto! I'd have been happy with that, too! That is really quite good for just the 135L. I guess I would have gone with a different white balance, but that is a pretty darn nice photo! Out of curiosity...did you use a tracking mount? Signal strength looks pretty good in that shot...a hell of a lot better than I've ever been able to get with my 100mm f/2.8. Stars are nice and round, too...something I've never been able to get without tracking.


----------



## jrista (Jan 5, 2014)

*Re: Deep Sky Astrophotography*



Quasimodo said:


> This is imho the most inspirational thread I have read in this forum for quite a while!
> 
> I have never tried astrophoto myself (except when I was lucky to borrow the 800/5.6 with a 2xIII TC to take picture of the moon, but that would hardly count as the moon is very bright so the exposure time is very short).
> 
> I have been reading this whole thread on my ipad retina, and it has quite good resolution. However, due to the restrictions on image size here in CR, I would have loved to see full resolution images of your beautiful pictures if you guys have posted them somewhere else?



Glad your finding it inspirational!  I find the sky to be quite inspiring in and of itself. 

Regarding larger resolution images, personally, I don't have anything really high resolution. You can find all my work at jonrista.com, and the images there will be a little higher resolution. I downsample them all right now to reduce noise (at full size, they really don't look all that good.) Once I am able to get a tracking mount, I hope to produce MUCH larger and more detailed images, and I'll happily share them. Not sure when that will be, though...few months away at least, if not the end of the year.


----------



## jrista (Jan 5, 2014)

*Re: Deep Sky Astrophotography*

While out at my dark skies site the other day, I also managed to get some wider field milky way shots. I think you can even see some airglow in these photos (the green and red haze in the bottom half):


----------



## scyrene (Jan 5, 2014)

*Re: Deep Sky Astrophotography*



jrista said:


> Hmm! I'll have to check out Astronomik's filters for the supertelephoto lenses. I have the 600/4 L II, which is basically like a good Apochromatic refractor. I have my eye on the Celestron CGEM DX mount, which is about $1200 alone, and it should be able to hold my lens and camera quite easily. Having a light pollution filter would make it a lot easier for me to do some deep sky astrophotography without having to find time to drive an hour or so out of town to find clean dark skies. Thanks for the tip!
> 
> Ditto! I'd have been happy with that, too! That is really quite good for just the 135L. I guess I would have gone with a different white balance, but that is a pretty darn nice photo! Out of curiosity...did you use a tracking mount? Signal strength looks pretty good in that shot...a hell of a lot better than I've ever been able to get with my 100mm f/2.8. Stars are nice and round, too...something I've never been able to get without tracking.



I've posted a couple of pics here to show how it works. The filters are almost exactly the same size as the glass window in the filter holder, so you just balance/wedge it in there. It can fall out (into the lens!) so you have to be careful, although it can be retrieved with difficulty.

I've also included my best shot so far, since others are including photos. It's the North America Nebula with the 50D, UHC clip filter, and 100L macro + Kenko 2x teleconverter. Magic Lantern for bulb time lapse, which automates the capture process once it's aligned. Hand stacked and processed in Gimp, finished in Lightroom. 136x1mins at ISO 6400.

On the subject of star shape, the clip filter deforms bright stars to the shape of its opening - roughly a circle with the top and bottom cut off - at least shooting at wider apertures. And the coloured haloes only appear around medium-brightness stars, not the faintest, nor the very brightest. Not quite sure why.


----------



## Don Haines (Jan 5, 2014)

*Re: Deep Sky Astrophotography*

Still playing and learning......


----------



## emag (Jan 5, 2014)

*Re: Deep Sky Astrophotography*

I've used various astro software over the years, but I think only once or twice did I manually stack images. I do all my stacking with DeepSkyStacker - free and quick to learn. The resulting 16 bit tiff is opened in Adobe Camera Raw, tweaked and sent to Photoshop for final work. I typically take 90 second exposures but sometimes shorter exposures for brighter objects like globulars and planetary nebulae. I've been off work for two weeks and had ONE night suitable for any kind of astro work, and not very well suited at that, upper atmosphere turbulence was horrible and I was doing some imaging of Jupiter. Comparing the use of a modified webcam to the crop video with a 60D for a Registax presentation with my local astronomy club next week. I use a 60D, an astro modified 40D and once the weather clears I'll be using a 6D. I have assorted clip filters for the 40D, they allow me to image from my light-polluted back yard. The 40D is somewhat noisy and prone to banding, but the trade off is Ha sensitivity. I gotta believe a modified 6D would be exquisite for astro.

I would love to have a cooled CCD imager, but it's difficult to justify to myself, let alone SWMBO. Our observing season in the FL Panhandle is just too short, and the CCD would be suitable for ONLY astronomy, unlike a DSLR.

Without tracking, I only shoot wide field or time lapse. I've got two CG5 GOTO mounts, one carries a C8 and the other a small refractor with a piggybacked camera/telephoto combo. I've a non-GOTO fork-mounted C9.25 that tracks phenomenally well....but that scope seems to get 5lbs heavier every year. (I realize this isn't a 'for sale' site, but if anyone with a younger/stronger back is visiting NW Florida and interested yer welcome to come take a look.)

Here's an assortment of images, the Trapezium with un-modified 40D (C9.25 with 2XTC), M51 with un-modified 60D (C8 with f/6.3 focal reducer) and the rest with a modified 40D (300mm/4L or 4 inch f/5 refractor).

Other such stuff is at pbase(dot)com/emagowan/astrophotography


----------



## lol (Jan 5, 2014)

*Re: Deep Sky Astrophotography*

The Andromeda I posted was, as said, one of my older ones. I've since paid more attention to removing the blue hue. That shot was more to show the 135L and red halo around brighter stars which hinders its use if you want to do multiple colour channels at once.

Since I didn't mention it, that was at 1 minute exposures. That does need tracking, and I used the Astrortac at the time. I don't have notes on the ISO used but I normally leave it pretty high, either 1600 or 3200. For sure, once you can get a bit of exposure time thrown at it, it helps a lot with getting the dark stuff out. Then repeat the exposures as much as you can to get the noise down.

I played with DSS early on, but never really got on with it. I've gone to PixInsight but it isn't cheap and has more of a learning curve to it.




Here's a more recent attack on it. 450D with all filters removed. Astronomik CLS-CCD. Sigma 120-300 f/2.8 OS EX at 300mm f/2.8. 2 minute exposures. Note the stars don't suffer the red glow the 1235L does.

Due to the light pollution where I live, I can't do really long exposures even with filters. I can perhaps get 4 minutes usefully with a narrowband filter at f/2.8, after which I'm just picking up the noise floor.

If I stop being lazy, I really want to have a go with the Rosette nebula with the 300/2.8. I've only tried that with the 135L in the past and it is rather small in it.


----------



## emag (Jan 6, 2014)

*Re: Deep Sky Astrophotography*

Nice!! That lens looks like a real performer. I REALLY liked your Veil shots on SGL, particularly the random L channel shot.


----------



## jrista (Jan 6, 2014)

*Re: Deep Sky Astrophotography*

Thanks emag, scyrene, lol for your contributions! Great stuff! I'm really feeling the pain of not having a tracking mount. I think I'll pick one up, along with a basic spotting scope, for use with my 600mm lens + 2x TC until I have the chance to buy an actual telescope. I love Celestron's mounts....I might pick up the basic CGEM to start. 



lol said:


> I played with DSS early on, but never really got on with it. I've gone to PixInsight but it isn't cheap and has more of a learning curve to it.



I hear PixInsight is pretty good. I also hear good things about Nebulosity. I've read through Nebulosity's manual, it sounds pretty powerful. I'll check out PixInsight next. DSS is an ok tool for being free, but it has it's limitations, and tweaking the final result can be a real pain. A more powerful tool, even if it costs money, would be well worth it. 



lol said:


> Here's a more recent attack on it. 450D with all filters removed. Astronomik CLS-CCD. Sigma 120-300 f/2.8 OS EX at 300mm f/2.8. 2 minute exposures. Note the stars don't suffer the red glow the 1235L does.
> 
> Due to the light pollution where I live, I can't do really long exposures even with filters. I can perhaps get 4 minutes usefully with a narrowband filter at f/2.8, after which I'm just picking up the noise floor.



Looks great! I'll have to look more into light pollution filters. I live fairly close to Denver, and there can be quite a LOT of light pollution here...so I am not sure if it would really be worth it. At ISO 3200, I can only expose for maybe 10-15 seconds before it really doesn't become any more worth while to expose longer, because the light pollution shifts the entire histogram right (lifts the black level considerably). 



Don Haines said:


> Still playing and learning......



Single frame, or stack from a web cam? If you have a web cam, you might try setting up some kind of contraption to attach it to your lens, and let it rip for about a minute. Then, you can use the tool Registax to identify the best frames, stack em, and you can get some really AMAZING planetary results. Each individual frame looks super crappy, but people have been creating some truly awesome, and often highly detailed, results with Registax and around 1000-1500 frames from basic web cams. Even some RGB astrocams like Celestron's Skyris is just a webcam in a more advanced enclosure with astro-specific features.


----------



## Don Haines (Jan 6, 2014)

*Re: Deep Sky Astrophotography*



jrista said:


> Don Haines said:
> 
> 
> > Still playing and learning......
> ...


60D shooting video through an 8 inch telescope.... 1900 frames extracted from the video and run through registax. The atmospheric distortion was really bad that night and all the frames are poor, but the result was much better than any individual frame.

I want to try digiscoping through the telescope, but for the last two months the only times it has been clear at night the temperature has been -25C or colder.... Right now it is freezing rain, tomorrow night is supposed to be minus 29.... A wild winter!


----------



## jrista (Jan 6, 2014)

*Re: Deep Sky Astrophotography*



Don Haines said:


> jrista said:
> 
> 
> > Don Haines said:
> ...



Ah, so you are using Registax. Great program! I've tried using my 7D video to image Jupiter...I can't get the same kind of results others get with even just a webcam jury-rigged to a telescope. I think part of it is that the web cams have really tiny pixels which capture enough detail, where as my 7D has pixels that are about 2x - 3x larger...and it's video is pretty crappy.



Don Haines said:


> I want to try digiscoping through the telescope, but for the last two months the only times it has been clear at night the temperature has been -25C or colder.... Right now it is freezing rain, tomorrow night is supposed to be minus 29.... A wild winter!



Yeah, crazy winter indeed. It was around 10°C two days ago. The last couple of days, it's been below zero here in Colorado! Right now it is -26.5°C!  *shivvvver* We got about 8-10 inches of snow, the most we've had all winter (previous high was 3"), and it is still snowing. At least we haven't had any freezing rain yet...although I hear the north east region of the US is slated for some nasty freezing rain and sleet, then more sub-zero weather after that, making for some terrible driving conditions.


----------



## emag (Jan 27, 2014)

*Re: Deep Sky Astrophotography*

Last night was one of the rare nights this winter I've been able to use the scope, and only for about 3 hours at that, the seeing went to crap by 9PM. A shot of M81 (bottom) and M82 (top). The bright star in M82 is a supernova that became visible in January. About 12 million light years away.....I may be front focusing a few million miles. Taken with a 6D through an 8 inch scope, 1260mm effective focal length, f/6.3. Stack of 10 shots, each 30 seconds. I had some (operator) issues with my mount so there's a bit of trailing in the image.


----------



## CarlTN (Jan 27, 2014)

*Re: Deep Sky Astrophotography*



lol said:


> I had a chat with Astronomik in the past about their narrowband filters and fast lenses. I think the e-mails are on my work account so I can't find it right now. Although their website rates them as usable from f/2.8, they said f/2.0 was ok. Any benefit from going even faster will reduce.
> 
> I did a lot of my early attempts with the 135L wide open. Note the lens is rather horrible for wideband imaging as the red focus is some way off that of green/blue. It is fine for narrowband.
> 
> ...



Very nice!


----------



## wearle (Jan 27, 2014)

*Re: Deep Sky Astrophotography*

To all,

Here's a wide-field image of the Galactic Dark Horse Nebula. Numerous dark nebula come together to form a horse if rotate clock-wise 90 degrees. This was taken with a modified Canon 5D2 and a Canon 200mm f/2.0L stopped down to f/4.0. It is an integration of 25 four-minute exposures. It was calibrated using six dark frames, twenty biases, and twenty flats. All calibration and processing was done in PixInsight.

Thanks for looking,

Wade


----------



## CarlTN (Jan 27, 2014)

*Re: Deep Sky Astrophotography*



wearle said:


> To all,
> 
> Here's a wide-field image of the Galactic Dark Horse Nebula. Numerous dark nebula come together to form a horse if rotate clock-wise 90 degrees. This was taken with a modified Canon 5D2 and a Canon 200mm f/2.0L stopped down to f/4.0. It is an integration of 25 four-minute exposures. It was calibrated using six dark frames, twenty biases, and twenty flats. All calibration and processing was done in PixInsight.
> 
> ...



Lovely, makes me wonder what a higher rez version of your image (or part of it) would look like...


----------



## Mr Bean (Jan 27, 2014)

*Re: Deep Sky Astrophotography*

Some really beaut pics in this thread. Unfortunately, I don't have a tracking mount, and I wondered what was possible with a 5D3 + 300mm f4. While it's nothing flash, I was impressed what could be recorded in a 1 second exposure @ 3,200 ISO 

Orion Nebula.


----------



## jrista (Jan 27, 2014)

*Re: Deep Sky Astrophotography*



Mr Bean said:


> Some really beaut pics in this thread. Unfortunately, I don't have a tracking mount, and I wondered what was possible with a 5D3 + 300mm f4. While it's nothing flash, I was impressed what could be recorded in a 1 second exposure @ 3,200 ISO
> 
> Orion Nebula.



Good start. The trick is stacking. Your single frame here is dim and noisy, as a single frame. Now, if you take about 100 of these 1 second shots, then align and stack them, you can greatly reduce the noise, and "fill in the blanks" and improve detail. Once you have a stacked image with lower noise and more detail, you will have MUCH more freedom to push the exposure around in ACR/LR or Photoshop. The grainy, poorly saturated example here could become a pretty amazing photo of the Orion nebula. 

Another tip. If you live in or near a city, head out of town by about 50 miles (preferably at least the same distance from any other city). That should get you much darker skies. Darker skies mean more nebula detail, less noise, and even better results after stacking.

For stacking software, I recommend starting out with DeepSkyStacker. It's pretty easy...the trickiest part is "stretching" the exposure after DSS is done doing it's thing. The curves editor in DSS is pretty quirky, and not the easiest thing to use. Play with it for a couple of hours, though, and you'll start to get the hang of it. 

Trust me, though...with that lens and the 5D III, you can get MUCH, MUCH better results...just takes a little more effort.


----------



## jrista (Jan 27, 2014)

*Re: Deep Sky Astrophotography*



wearle said:


> To all,
> 
> Here's a wide-field image of the Galactic Dark Horse Nebula. Numerous dark nebula come together to form a horse if rotate clock-wise 90 degrees. This was taken with a modified Canon 5D2 and a Canon 200mm f/2.0L stopped down to f/4.0. It is an integration of 25 four-minute exposures. It was calibrated using six dark frames, twenty biases, and twenty flats. All calibration and processing was done in PixInsight.
> 
> ...



Wonderful! It just blows me away how many stars there are near and in the galactic core. The density is stunning!

So, with a modified 5D2, I assume that means the UV/IR cutoff filter (and maybe low pass filter) were removed?


----------



## jrista (Jan 27, 2014)

*Re: Deep Sky Astrophotography*



emag said:


> Last night was one of the rare nights this winter I've been able to use the scope, and only for about 3 hours at that, the seeing went to crap by 9PM. A shot of M81 (bottom) and M82 (top). The bright star in M82 is a supernova that became visible in January. About 12 million light years away.....I may be front focusing a few million miles. Taken with a 6D through an 8 inch scope, 1260mm effective focal length, f/6.3. Stack of 10 shots, each 30 seconds. I had some (operator) issues with my mount so there's a bit of trailing in the image.



Not bad! Kind of cool to capture a supernova in a distant galaxy. I always watch this blog for updates on interesting phenomena like that:

http://remanzacco.blogspot.com

They have a lot of info on solar system object, comets and asteroids and whatnot, but they also track extra-solar system events as well.


----------



## Mr Bean (Jan 27, 2014)

*Re: Deep Sky Astrophotography*



jrista said:


> Mr Bean said:
> 
> 
> > Some really beaut pics in this thread. Unfortunately, I don't have a tracking mount, and I wondered what was possible with a 5D3 + 300mm f4. While it's nothing flash, I was impressed what could be recorded in a 1 second exposure @ 3,200 ISO
> ...


Thanks for the tips jrista. I might give it a go tonight 

The last time I did any "real" astrophotography was back with Halleys Comet using Fuji gas hypered film, standing in the middle of a paddock all night, keeping the scope on track 

Oh, and I live on the outskirts of Melbourne, where the skies are pretty dark. This one was taken from my house.


----------



## jrista (Jan 27, 2014)

*Re: Deep Sky Astrophotography*



Mr Bean said:


> Oh, and I live on the outskirts of Melbourne, where the skies are pretty dark. This one was taken from my house.



Check how your light pollution is with this map:

https://mywebspace.wisc.edu/dlorenz/web/astronomy/lp2006/overlay/dark.html

Yellow and up are bad. Green is ok. You really want to be in blue or gray areas, where the skies are really dark. Trust me, I've experimented very recently with how much light pollution affects results. I live in a brighter yellow area bordering on an orange area in Denver, Colorado. LP is pretty bad over my house, even though it doesn't seem as much to my bare eyes. Green areas improve quite a bit. Blue areas are amazing, the number of stars increases considerably, and astrophotography gets much better. 

Gray areas are just phenomenal. The two lighter regions of gray conform to Bortle Scale level between 2 and 1...very dark skies or "truly dark skies". You can see an unbelievable amount of stars, everything is crisp and clear, you might even get a glimpse of airglow. The milky way is brilliant, and at the right times of the year, you can see the zodiacal light (provided it isn't obscured by LP bubbles on the horizon. Blue and gray areas of the map above are really where you want to be for AP. Think of it like stops on a camera...Blue is about a stop worse than gray, green is about a stop worse than blue, yellow a stop worse than green, etc. Each time you get closer to the main source of light pollution, you lose about half your ability to deeply image the night sky.

You can expose for almost twice as long and all that as well (i.e. you can expose for maybe 10 minutes in a green region, but 20 minutes or longer in blue and gray regions) as you move out to darker regions. BTW, there are three levels of gray. The darkest gray are what they call "Exceptionally Dark Skies", and has a Bortle Scale level of 1. There are actually relatively few regions of civilized Earth that are still this dark. Australia appears to have more than normal. Canada also has large regions of exceptionally dark skies. There are small pockets of exceptionally dark skies in the US and Europe. Excptionally dark skies are where they put the big scientific observatories, especially when they are on mountaintops. If you have the opportunity to visit an exceptionally dark sky, it'll just blow your mind how clear and bright the night sky really is. It's a thing of wonder, and most people in the "civilized" world rarely ever see it. The milky way is so relatively so bright it will actually cast shadows, the zodiacal light (which I've never seen under these conditions) is apparently "annoyingly bright" (which came from an astrophotographer, so take that in context!), and the number of deep sky objects that you can see with your naked eye maxes out...magnitude 8 stellar objects are visible to the naked eye (which is really amazing, given that most people on earth are only able to see magnitude 6 and larger stars, a whole two orders of magnitude difference, and in cities magnitude four and larger is the limiting magnitude. If you live in a metropolitan heart, where LP is at its highest, you can only see things magnitude 0 and brighter, so mostly planets, the brightest stars, the moon....no milky way at all, no deep sky objects, you can't make out most constellations because there simply aren't enough stars visible. Light pollution is kind of a terrible thing really, a travesty against the natural state of night...massive waste of energy to light so much of the earths surface up like that when most of it is suburban regions full of sleeping families...they could all turn off their lights, turn of the street lights, etc.) 

I have not had a chance to photograph in the night sky under exceptionally dark skies. I'm hoping to get up to the top of the continental divide in one of the couple spots where you have exceptionally dark skies and image the milky way and zodiacal light when the latter rolls around again this spring.

Anyway...if your on the outskirts of Melbourne, but are still under green, yellow, orange or red, try heading out to darker skies. The difference is worth it.


----------



## Mr Bean (Jan 27, 2014)

*Re: Deep Sky Astrophotography*



jrista said:


> Mr Bean said:
> 
> 
> > Oh, and I live on the outskirts of Melbourne, where the skies are pretty dark. This one was taken from my house.
> ...


Thanks for the link, that's really neat. Looks like I'm pale yellow, moving into green. It's not bad, considering I'm an hours drive from the City. Last October I went to Tasmania for a week. The areas around Cradle Mountain were stunning for clear night skies. I'll have to head back later this year 

I've just downloaded DeepSkyStacker. I'll go out and try again, now that Orion is up


----------



## jrista (Jan 27, 2014)

*Re: Deep Sky Astrophotography*



Mr Bean said:


> jrista said:
> 
> 
> > Mr Bean said:
> ...



Ah, that is really funny. Orion just set maybe an hour ago here. My favorite constellation...I don't have much time left to image it. I'm trying to find a good equatorial mount, an autoguider, and get some custom telescope rings built for my 600mm lens so I can use it as an apochromatic refracting telescope. I don't know if I'll find what I need before Orion sets for good...it is up near zenith by 8pm now....and directly overhead before 10pm...it's fading fast...


----------



## wearle (Jan 27, 2014)

*Re: Deep Sky Astrophotography*



CarlTN said:


> Lovely, makes me wonder what a higher rez version of your image (or part of it) would look like...


Thanks! 

Here's a link to a higher resolution image of the Galactic Dark Horse Nebula.

http://www.northwest-landscapes.com/images/deepsky/wide-field/big_E_5d2_200mm_1600x2400.jpg

Wade


----------



## wearle (Jan 27, 2014)

*Re: Deep Sky Astrophotography*



jrista said:


> Wonderful! It just blows me away how many stars there are near and in the galactic core. The density is stunning!
> 
> So, with a modified 5D2, I assume that means the UV/IR cutoff filter (and maybe low pass filter) were removed?


Thanks!

You should check out the link to the higher resolution version I just posted. 

I purchased the camera from Astro Hutech with Option T. It includes a more astro-friendly bandpass filter. It works very well for astrophotography. You can still use it as a regular camera too if you create a custom white balance.

Wade


----------



## CarlTN (Jan 27, 2014)

*Re: Deep Sky Astrophotography*



wearle said:


> CarlTN said:
> 
> 
> > Lovely, makes me wonder what a higher rez version of your image (or part of it) would look like...
> ...



Thanks very much, that is mind-blowing!! Do you mind if I print one for myself?


----------



## wearle (Jan 27, 2014)

*Re: Deep Sky Astrophotography*



CarlTN said:


> Thanks very much, that is mind-blowing!! Do you mind if I print one for myself?



Thanks, there is definitely enough stars in the image to be mind-blowing.  

I would prefer you not to make a print from my image. If you would like a print, I can make you one at a very reasonable cost, and it would look a lot better than what could be achieved with the jpeg version. You can contact me privately if you like.

Wade


----------



## CarlTN (Jan 27, 2014)

*Re: Deep Sky Astrophotography*



wearle said:


> CarlTN said:
> 
> 
> > Thanks very much, that is mind-blowing!! Do you mind if I print one for myself?
> ...



Thanks Wade, I will contact you.


----------



## wearle (Jan 28, 2014)

*Re: Deep Sky Astrophotography*

To all,

Here's a wide-field image of the North America Nebula. This was taken with a modified Canon 5D2 and a Canon 200mm f/2.0L stopped down to f/4.0. It is an integration of 24 four-minute exposures. It was calibrated using six dark frames, twenty biases, and twenty flats. All calibration and processing was done in PixInsight.

Thanks for looking,

Wade


----------



## jrista (Jan 28, 2014)

*Re: Deep Sky Astrophotography*



wearle said:


> To all,
> 
> Here's a wide-field image of the North America Nebula. This was taken with a modified Canon 5D2 and a Canon 200mm f/2.0L stopped down to f/4.0. It is an integration of 24 four-minute exposures. It was calibrated using six dark frames, twenty biases, and twenty flats. All calibration and processing was done in PixInsight.
> 
> ...



How do you like PixInsight? I'm getting into deep sky AP now, and am in the process of buying a mount and software. I was planning to use something like Nebulosity or maybe BackyardEOS for control software, PHD for guiding, and Photoshop for processing. But Pixinsight seems pretty popular these days.


----------



## Canon1 (Jan 28, 2014)

*Re: Deep Sky Astrophotography*



wearle said:


> To all,
> 
> Here's a wide-field image of the North America Nebula. This was taken with a modified Canon 5D2 and a Canon 200mm f/2.0L stopped down to f/4.0. It is an integration of 24 four-minute exposures. It was calibrated using six dark frames, twenty biases, and twenty flats. All calibration and processing was done in PixInsight.
> 
> ...



Amazing. Do you have a website? I'd love to see more of your work. TFS.


----------



## wearle (Jan 28, 2014)

*Re: Deep Sky Astrophotography*



jrista said:


> How do you like PixInsight? I'm getting into deep sky AP now, and am in the process of buying a mount and software. I was planning to use something like Nebulosity or maybe BackyardEOS for control software, PHD for guiding, and Photoshop for processing. But Pixinsight seems pretty popular these days.


I believe PixInsight is one of the best astrophotography processing software packages out there. I've been using it since the PixInsight LE days. There is a steep learning curve; however, the PixInsight Forum is an awesome place to learn it and support is second to none. 

Wade


----------



## wearle (Jan 28, 2014)

*Re: Deep Sky Astrophotography*



Canon1 said:


> Amazing. Do you have a website? I'd love to see more of your work. TFS.


Thanks! 

I have two websites. One is old, and I haven't updated it in a long time; however, it does allow viewing of higher resolution versions of my astrophotography images.

http://www.northwest-landscapes.com/

My new site has the most up-to-date images and includes the older material, but you can't view any images higher than 960 pixels in the long dimension.

http://thomaswearlephotography.smugmug.com/

Wade


----------



## jrista (Jan 28, 2014)

*Re: Deep Sky Astrophotography*



wearle said:


> jrista said:
> 
> 
> > How do you like PixInsight? I'm getting into deep sky AP now, and am in the process of buying a mount and software. I was planning to use something like Nebulosity or maybe BackyardEOS for control software, PHD for guiding, and Photoshop for processing. But Pixinsight seems pretty popular these days.
> ...



Yeah, I've heard it's a bit of an odd piece of software, but it seems it's becoming almost ubiquitous amongst astrophotographers for processing. Once I get a telescope, I'll give it a whirl.


----------



## scyrene (Jan 28, 2014)

*Re: Deep Sky Astrophotography*



wearle said:


> To all,
> 
> Here's a wide-field image of the North America Nebula. This was taken with a modified Canon 5D2 and a Canon 200mm f/2.0L stopped down to f/4.0. It is an integration of 24 four-minute exposures. It was calibrated using six dark frames, twenty biases, and twenty flats. All calibration and processing was done in PixInsight.
> 
> ...



Very impressive. I've been looking to get that lens myself for this purpose (among others). From your description, I'm guessing it's a pretty dark site?


----------



## wearle (Jan 29, 2014)

*Re: Deep Sky Astrophotography*



scyrene said:


> Very impressive. I've been looking to get that lens myself for this purpose (among others). From your description, I'm guessing it's a pretty dark site?



Thanks! 

It's a very dark site. I measured it last Summer, and it was approaching 22.0 visual magnitudes per square arc-second. The only problem is eastern Oregon. It's rarely clear in the Winter. The Summer is generally clear, but then your contending with smoke-filled skies from wildfires.  When things do work out, I get about 6-8 opportunities a year during the New Moon window.

Wade


----------



## jrista (Jan 29, 2014)

*Re: Deep Sky Astrophotography*



wearle said:


> scyrene said:
> 
> 
> > Very impressive. I've been looking to get that lens myself for this purpose (among others). From your description, I'm guessing it's a pretty dark site?
> ...



Have you ever thought of narrow band imaging? Especially with the 3nm filters we have these days, you can even image DURING the full moon, and still get high SNR results that produce beautiful grayscale results (H-a only) or mapped images (S-II, H-a & O-III). I live under moderately light polluted skies. I was originally thinking about using an LPR, but I think now that I'm going to go all in for 3nm narrow band filters (although they are rather expensive...about $500-$700 each) so I can do more imaging from my home. 

Not much you can do about cloud cover, but since you can image during the entire lunar cycle, you get a lot more cuddle time with your scope.


----------



## wearle (Jan 30, 2014)

*Re: Deep Sky Astrophotography*



jrista said:


> Have you ever thought of narrow band imaging? Especially with the 3nm filters we have these days, you can even image DURING the full moon, and still get high SNR results that produce beautiful grayscale results (H-a only) or mapped images (S-II, H-a & O-III). I live under moderately light polluted skies. I was originally thinking about using an LPR, but I think now that I'm going to go all in for 3nm narrow band filters (although they are rather expensive...about $500-$700 each) so I can do more imaging from my home.
> 
> Not much you can do about cloud cover, but since you can image during the entire lunar cycle, you get a lot more cuddle time with your scope.



I do image in H-alpha, but only with my CCD camera. 

I have a 5nm H-alpha filter. Keep in mind, the 3nm H-alpha filter blocks out the N2 spectrum so your results will look a little different than most narrowband H-alpha filters which are wide enough to capture N2.

You still lose contrast when imaging during "moon-up" even with narrowband filters. The effect just isn't as pronounced. Because of this, I generally do not image while the Moon is up. 

It takes me about 90 minutes driving time to get to my dark site so I'm probably too picky when it comes to transparency. I could probably double my trips if I wasn't so picky. 

Wade


----------



## wearle (Jan 30, 2014)

*Re: Deep Sky Astrophotography*

To all,

Here's a wide-field image of the Rosette and Cone Nebula region. This was taken with a modified Canon 5D2 and a Canon 200mm f/2.0L stopped down to f/4.0. It is an integration of 16 four-minute exposures. It was calibrated using six dark frames, twenty biases, and twenty flats. All calibration and processing was done in PixInsight.

Thanks for looking,

Wade


----------



## wearle (Jan 30, 2014)

*Re: Deep Sky Astrophotography*

To all,

This is not quite deep-sky, but might be "landscape". 

This is a composite image of the 2012 Perseid Meteor shower taken with a Canon 1DX and a rented Canon 8-15mm f/4.0L lens. The underlying background is a single image. I captured meteors throughout the night and picked the brightest ones to copy onto the background image. LightRoom and Photoshop CC were used to make the composite.

Thanks for looking,

Wade


----------



## wearle (Jan 30, 2014)

*Re: Deep Sky Astrophotography*



wearle said:


> This is a composite image of the 2012 Perseid Meteor shower taken with a Canon 1DX and a rented Canon 8-15mm f/4.0L lens.



Oops, that should be the 2013 Perseid Meteor Shower. :-[

Wade


----------



## jrista (Jan 30, 2014)

*Re: Deep Sky Astrophotography*



wearle said:


> jrista said:
> 
> 
> > Have you ever thought of narrow band imaging? Especially with the 3nm filters we have these days, you can even image DURING the full moon, and still get high SNR results that produce beautiful grayscale results (H-a only) or mapped images (S-II, H-a & O-III). I live under moderately light polluted skies. I was originally thinking about using an LPR, but I think now that I'm going to go all in for 3nm narrow band filters (although they are rather expensive...about $500-$700 each) so I can do more imaging from my home.
> ...



Hmm, interesting about the N2 band. And 5nm filters are about $300 cheaper than 3nm filters are (~$600 vs. $900), so a decent savings in money.


----------



## wearle (Jan 30, 2014)

*Re: Deep Sky Astrophotography*



jrista said:


> Hmm, interesting about the N2 band. And 5nm filters are about $300 cheaper than 3nm filters are (~$600 vs. $900), so a decent savings in money.



I would recommend getting the H-alpha in 5nm, S2 in 3nm, and O3 in 3nm. The only drawback to 3nm is if you have a fast system (i.e. f/3 or faster). They become less efficient and your almost better off getting all 5nm.

Wade


----------



## jrista (Jan 30, 2014)

*Re: Deep Sky Astrophotography*



wearle said:


> jrista said:
> 
> 
> > Hmm, interesting about the N2 band. And 5nm filters are about $300 cheaper than 3nm filters are (~$600 vs. $900), so a decent savings in money.
> ...



Yeah, I read a bit about the f/3 issue on Astrodon's site. I am actually planning to use my 600mm f/4 lens as a fast APO refractor. Probably with an SBIG STF-8300m in the long run, with the filter ring accessory. Is f/4 fast enough to cause problems?


----------



## scyrene (Jan 31, 2014)

*Re: Deep Sky Astrophotography*



wearle said:


> To all,
> 
> This is not quite deep-sky, but might be "landscape".
> 
> ...



Without a doubt, that's the best meteor picture I've ever seen. Well done!


----------



## wearle (Feb 1, 2014)

*Re: Deep Sky Astrophotography*



jrista said:


> Yeah, I read a bit about the f/3 issue on Astrodon's site. I am actually planning to use my 600mm f/4 lens as a fast APO refractor. Probably with an SBIG STF-8300m in the long run, with the filter ring accessory. Is f/4 fast enough to cause problems?



You should be okay. You might loose a little transmission efficiency, but probably not enough to notice. 

Wade


----------



## wearle (Feb 1, 2014)

*Re: Deep Sky Astrophotography*



scyrene said:


> Without a doubt, that's the best meteor picture I've ever seen. Well done!



It takes a lot of work to produce these composites so I really appreciate your comment.

Wade


----------



## scyrene (Feb 3, 2014)

*Re: Deep Sky Astrophotography*

I hope it's not inappropriate, but my last astro effort (and my only one recently) was the following. California Nebula, suburban/semi-rural site, UHC filter. I've been repeatedly astounded how bright this is in ultra widefield (~14mm) shots, so I decided to go closer. But no flats, which seem to disagree with this lens (pity), and no darks cos I forgot. Still...


----------



## jprusa (Feb 3, 2014)

*Re: Deep Sky Astrophotography*



wearle said:


> scyrene said:
> 
> 
> > Without a doubt, that's the best meteor picture I've ever seen. Well done!
> ...



Well done !!!


----------



## jprusa (Feb 3, 2014)

*Re: Deep Sky Astrophotography*



wearle said:


> To all,
> 
> Here's a wide-field image of the Rosette and Cone Nebula region. This was taken with a modified Canon 5D2 and a Canon 200mm f/2.0L stopped down to f/4.0. It is an integration of 16 four-minute exposures. It was calibrated using six dark frames, twenty biases, and twenty flats. All calibration and processing was done in PixInsight.
> 
> ...



Very nice Wade .


----------



## jrista (Feb 3, 2014)

*Re: Deep Sky Astrophotography*



scyrene said:


> I hope it's not inappropriate, but my last astro effort (and my only one recently) was the following. California Nebula, suburban/semi-rural site, UHC filter. I've been repeatedly astounded how bright this is in ultra widefield (~14mm) shots, so I decided to go closer. But no flats, which seem to disagree with this lens (pity), and no darks cos I forgot. Still...



Nice shot. It looks a little overprocessed...saturation is a bit harsh, and the stars have that funky halo around them. I'd pull back on the processing a bit, reduce saturation...and that would actually probably help bring out more subtlety in nebula detail. 

Out of curiosity, how long was the exposure?


----------



## wearle (Feb 5, 2014)

*Re: Deep Sky Astrophotography*

To all,

Here's a wide-field image of the dark nebula in Aquila. This is a three frame mosaic. It was taken with a modified Canon 5D2 and a Canon 200mm f/2.0L stopped down to f/4.0. Each frame is an integration of 10 four-minute exposures. Each frame was calibrated using six dark frames, twenty biases, and twenty flats. All calibration and processing was done in PixInsight.

I may try to add a few frames to the right side of the mosaic this year as it is just too dark. That's what happens when you grab a portion of the Great Rift. 

Thanks for looking,

Wade


----------



## scyrene (Feb 14, 2014)

*Re: Deep Sky Astrophotography*



jrista said:


> scyrene said:
> 
> 
> > I hope it's not inappropriate, but my last astro effort (and my only one recently) was the following. California Nebula, suburban/semi-rural site, UHC filter. I've been repeatedly astounded how bright this is in ultra widefield (~14mm) shots, so I decided to go closer. But no flats, which seem to disagree with this lens (pity), and no darks cos I forgot. Still...
> ...



Ah, the haloes are due to using a very wide aperture with the UHC filter, which they're not meant for. I get big red haloes round the medium-brightness stars, so I use 'remove colour fringing' in Lightroom, but that does leave these grey haloes, which isn't what I'd prefer, but it's a limitation of my setup at present. I'd like to stop down to reduce this, but I can't afford the light loss, as my tracking won't go beyond 1-2m mins per subframe. Also using this lens wide open creates all sorts of weird colour casts across the image, so it needs a bit more processing than the 100L Macro, for instance. The upshot is you get a lot more faint stars.

I rather like the saturation, though I can understand why some would tone it down. It's always a tough balance. This is 113x1min exposures at f/1.2 (50D @ ISO 1600)


----------



## jrista (Feb 27, 2014)

*Re: Deep Sky Astrophotography*



scyrene said:


> jrista said:
> 
> 
> > scyrene said:
> ...



You should look into getting Astronomy Tools. It's a set of PS actions that might help you with your halo problems. It's pretty cheap, around $20.


----------



## jrista (Feb 27, 2014)

*Re: Deep Sky Astrophotography*

So, I FINALLY got some clear sky for a period of several hours, and was finally able to create a nicer image of Horse Head and Flame Nebulas:




See at my blog

Integration of 1h 30m of subs. Not really enough to reduce noise to an acceptable level, I need about 5h total to really reduce noise. But I was able to stretch and enhance the nebula detail quite a bit! 

Stack of 30x180s @ ISO 400. Canon 7D, EF 600mm f/4 L II as telescope. Calibrated with 30 flats and 100 bias. 

See full size image at AstroBin:


----------



## CarlTN (Feb 27, 2014)

*Re: Deep Sky Astrophotography*



jrista said:


> So, I FINALLY got some clear sky for a period of several hours, and was finally able to create a nicer image of Horse Head and Flame Nebulas:
> 
> 
> 
> ...



Nice work. So there's no tracking device, correct? This is the full size image? So it's a crop of the image?


----------



## jrista (Feb 27, 2014)

*Re: Deep Sky Astrophotography*



CarlTN said:


> jrista said:
> 
> 
> > So, I FINALLY got some clear sky for a period of several hours, and was finally able to create a nicer image of Horse Head and Flame Nebulas:
> ...



Oh yes! There is tracking. Very accurate tracking, actually. I used an Orion Atlas EQ-G equatorial tracking mount, along with the ADM D-type side-by-side tandem saddle, in which my 600/4 II lens was mounted with a custom dovetail plate, and the Orion SSAG (StarShoot Auto Guider) was mounted next to it. The SSAG does autoguiding...it finds a star, then sends special instructions to the mount to keep that star in the exact same place at all times.

There is a total of 1 hour and 30 minutes exposure time here (it's called integration time, as it is not a single exposure, it's a calibrated stack of images). That was achieved by stacking 30x 180 second individual exposures, each of which were calibrated with a master flat frame (to reduce vignetting) and a master bias frame (to eliminate fixed sensor noise). There is no way you could do that without tracking. Tracking, and guiding, is essential to keep the shutter open that long without stars trailing (at 600mm, stars trail by 1/3rd of a second exposure without tracking). Tonight, I was able to get my mount aligned and guided well enough to get 0.08 RMS R.A. axis tracking precision, and 0.10 RMS Dec. axis tracking. I had minimal guiding corrections, once every several seconds at the most frequent, which is really very good. When guiding is worse than that, stars end up getting larger, sometimes misshapen. The stars in this shot are pretty round.

The only real problem is the field isn't entirely flat. I tried to flatten it, but that ended up making the corners bright, so I need to figure out how to fix that.

Regarding crop, it isn't quite the same as with standard photography. Since this is a stack of multiple frames, the total image size after stacking is usually larger than a single frame. The image near the edges is usually pretty ugly with stacking artifacts, so you usually crop inwards to get rid of that junk. After cropping, this image was still actually slightly larger than a standard 7D frame (5184x3456). I downsampled that by 50% when uploading to AstroBin, so the full size image you see there roughly represents the full 7D frame, even though it's 1/4 the size now.


----------



## philmoz (Feb 27, 2014)

*Re: Deep Sky Astrophotography*



jrista said:


> So, I FINALLY got some clear sky for a period of several hours, and was finally able to create a nicer image of Horse Head and Flame Nebulas:
> 
> 
> 
> ...



Awesome 8)

(I can feel a bout of GAS in my future.)

Phil.


----------



## CarlTN (Feb 27, 2014)

*Re: Deep Sky Astrophotography*



jrista said:


> CarlTN said:
> 
> 
> > jrista said:
> ...



That's quite interesting, and again, well done! A co-worker of my brother's, is trying a similar stacking technique, but he has no tracking device, and the image I saw was even smaller in pixel dimensions than this one. He's too stuck up to even talk to me about it, haha... 

In any case, keep up the good work! I hate to feed your maniacal ego though, but as I told you before, I do love astro images! It's great you are so committed to it. How do the cold temps affect your 600 lens? Does it frost any? I assume you use the hood? I guess you allow for the time to cool it down, as well as let it warm up gradually when you bring it in (maybe in an unheated garage or similar)? 

Btw I tried to see the ISS tonight, and never saw it. Kind of sucks because the sky was extremely clear, I had my Vanguard 8.5 x 45mm ED bino's out and all ready. I've seen it before, so it was odd I couldn't this time. I only saw about 15 high flying jet airliners and one turboprop that must have been at around 20,000 feet...and I could see it approaching from only 20 degrees above the horizon, so it was pretty far away at first. These bino's aren't quite Swarovski, they have loads more CA and astigmatism, but their "macro" contrast is actually superior...at least to the previous generation "Swarovision" that I compared them directly to for about 45 minutes...likely not the current generation though. But that's ok, I'd rather spend funds towards camera gear!


----------



## jprusa (Feb 27, 2014)

*Re: Deep Sky Astrophotography*



jrista said:


> So, I FINALLY got some clear sky for a period of several hours, and was finally able to create a nicer image of Horse Head and Flame Nebulas:
> 
> 
> 
> ...



Very nice Jon.


----------



## jrista (Feb 27, 2014)

*Re: Deep Sky Astrophotography*



CarlTN said:


> ... I hate to feed your maniacal ego though...



You know, you've been taking little jabs at me like that for days. I'm not really sure what set you off, but so long as you continue to slip little insults into your responses, I really have no reason to spend time responding to your questions. This isn't a thin-skin thing, either. It's simply a matter of principal. If you have a bone to pick with me, pick it, in PMs. Otherwise, just be cordial out in the public forums...that really isn't asking much.


----------



## scyrene (Feb 27, 2014)

*Re: Deep Sky Astrophotography*



jrista said:


> scyrene said:
> 
> 
> > jrista said:
> ...



I don't have Photoshop, I use Gimp. It's a lot of work, but the opportunities to shoot the night sky are so rare, it's not so bad - I can set aside a day or two every couple of months. Thanks though. I've found a better tracker, so I might well be able to use narrower apertures. Also, Astronomik have released full frame in-camera filters, so that should help too.


----------



## jrista (Feb 27, 2014)

*Re: Deep Sky Astrophotography*



scyrene said:


> jrista said:
> 
> 
> > scyrene said:
> ...



Have you tried just stopping down a third or two thirds of a stop? Quite often, with fast aperture lenses, that's all that's really necessary to clean up the bulk of optical aberrations.

That said, I'd get a better tracker regardless. The longer you can expose, the better. Signal strength is really the key thing that matters. Every time you reduce ISO by a stop, you can expose for twice as long. Going from say ISO 1600 to ISO 400 means you quadruple your signal strength, while only doubling your noise.


----------



## epsiloneri (Feb 28, 2014)

*Re: Deep Sky Astrophotography*

Nice image, and good to see that the 7D did not completely cut out the H-alpha. H-alpha regions must be some of the harder objects to image with a non-modified dSLR.



jrista said:


> CarlTN said:
> 
> 
> > ... I hate to feed your maniacal ego though...
> ...


Hehe... he actually gave you a compliment, although his German way of expressing it hides it pretty well ;D


----------



## eml58 (Feb 28, 2014)

*Re: Deep Sky Astrophotography*



jrista said:


> So, I FINALLY got some clear sky for a period of several hours, and was finally able to create a nicer image of Horse Head and Flame Nebulas:



Superb, simply superb.

Really, this takes dedication few of us have, well done.


----------



## CarlTN (Feb 28, 2014)

*Re: Deep Sky Astrophotography*



jrista said:


> CarlTN said:
> 
> 
> > ... I hate to feed your maniacal ego though...
> ...



Sorry to hurt your feelings, I will try to do better next time.


----------



## jrista (Feb 28, 2014)

*Re: Deep Sky Astrophotography*



epsiloneri said:


> Nice image, and good to see that the 7D did not completely cut out the H-alpha. H-alpha regions must be some of the harder objects to image with a non-modified dSLR.



The Astronomik CLS filter helps there. You have to expose for longer, but modern DSLR sensors don't completely cut off the deep reds. Less than 20% at H-a and even less at S-II get through, but over a long exposure duration, enough gets through that the red emissions get above the read noise floor.



epsiloneri said:


> jrista said:
> 
> 
> > CarlTN said:
> ...



Being called a Maniacal ego maniac isn't a compliment where I come from...



CarlTN said:


> jrista said:
> 
> 
> > CarlTN said:
> ...



LOL. Again, my "feelings" aren't hurt. You have had a persistent issue with anyone who ever dares to contradict your opinions in any forceful manner. It isn't just me, Neuro has been on the other end of it just as much, if not more. You have a serious ego problem yourself...although yours has nothing to do with being to big, it really has to do with you being a weakling when it comes to confrontation or a conflict of opinions, especially when our presented with facts that you cannot counter because your own are FLAWED. You want to confront me, Carl? CONFRONT ME! I'm sick and tired of pussyfooting around with you. Buck up, be a man, and speak your friggin mind. Enough of this pathetic taunting from the corners. It's just plain sad.

And just to be exceptionally clear on this, because you seem to have misunderstood in the past, you and I are not friends. We never have been friends. We never will be friends. I deal with you because everyone deals with you. We all have to DEAL with you. Beyond that, your a persistent pain in the ass, always whining, always flinging sad little insults from the periphery, unable to cope when your proven wrong...at which point you resort to everything other than the cold, hard, painful facts...to mind games and button pushing and whatever else you think might somehow trip the other person up. It's very trollish, actually.

So, either lay it on me, or just shut up. Because otherwise I'm just done dealing with you. It's a waste of time.


----------



## CarlTN (Feb 28, 2014)

*Re: Deep Sky Astrophotography*



jrista said:


> So, either lay it on me, or just shut up. Because otherwise I'm just done dealing with you. It's a waste of time.



It's good to see you are not angry with me, glad to hear that! Yes Jrista, you are not a maniacal ego maniac whatsoever, and you are not out to get off on proving everyone wrong, and how smart you are. You are not an immature self absorbed child whatsoever, are you? Nor were your feelings hurt (obviously). Since you're done dealing with me, that's fine, because I wasn't offering any deals, so we can both win on that one. 

I'm not sure what you'd like me to do, are you proposing marriage? I'm sorry, but I just can't relocate right now, and also, even though some say I wear pink tights...I actually don't swing that way (believe it or not).

I wasn't aware we were arguing about anything (photographic or otherwise), and as for me being wrong. I'll admit it when I am. And when I don't admit it, my posts just get deleted anyway. So you probably won't have to worry about this one for long.

I'm glad we could have this little chat, though. I feel so much better. Hope you've taken some more nice astro shots. This stacking method gets around the need to remove the IR filter, as you said, so that's good. However, the shooting and processing time is longer, isn't it? And the final output resolution is lower. 

How much of a price difference would just buying a telescope with a cooled CCD imager cost? Couldn't you get like a 6 or 8 inch scope for like $2k to $3k, and a quite decent imager for less than $10k? Total cost would be similar to maybe, I don't know, a grand or two more, than your 7D and 600 ii combo.

Either way though, some of the results you're getting are nice to look at.


----------



## jrista (Feb 28, 2014)

*Re: Deep Sky Astrophotography*



CarlTN said:


> jrista said:
> 
> 
> > So, either lay it on me, or just shut up. Because otherwise I'm just done dealing with you. It's a waste of time.
> ...



Well, there we go! At least I got an honest, unmitigated, clear and open opinion out of you. I'm not surprised about it, either. I suspect you would say the same thing about Neuro as well. I also suspect that most people would believe your wrong on all counts, about both of us, and anyone else you might have such a similar opinion of. But wow...good to have the air cleared! Maybe we can leave the underhanded sideline insults behind us now, and move on...? (Of course, you'll always be free to dish it all out in PMs if you just, you know, feel the hankering, and really, PMs, so everyone else doesn't have to "deal", you know?)



CarlTN said:


> How much of a price difference would just buying a telescope with a cooled CCD imager cost? Couldn't you get like a 6 or 8 inch scope for like $2k to $3k, and a quite decent imager for less than $10k? Total cost would be similar to maybe, I don't know, a grand or two more, than your 7D and 600 ii combo.



Alright. First, I am spending my precious personal time here not because I'm some maniacal egomaniac troll who gets his LULS from proving people wrong. I spend my time writing things like this for the simple purpose of sharing my knowledge (with the honest intention of helping others expand their skills or improve their knowledge), and to correct misconceptions, debunk myths, and otherwise root out the twisted and convoluted "factoids" that many anti-fans may spew in order to trick unsuspecting readers into thinking something that is just plain and simply not true. I have said this in the past, but I'll say it again, because it's true...I really don't care what people think of me. 

I care what people _think_, about information, the information they may be presented with and the context and other parties involved in an exchange of information, and when people misuse information to misinform and twist the facts, that bothers me. It happens a lot. We have quite a few members on this forum who just LOVE to twist and convolute the facts, either because they just despise the brand we all come here to talk about (i.e. Mikael) or because they have an agenda. THAT is why I persist in my extensively long, highly detailed posts. It isn't about me...it's really just about the facts. And that isn't for my own good...it's for the good of those who might actually take the time to read what I write. I want people to be well-informed about the facts, or educated enough to make a good judgment about subjective material when it arises (this is, after all, a rumors forum.) If you disagree, and truly think I'm wrong, and have the evidence to back up your opinion, prove it! I think I've proven myself that I'm quite capable of accepting when I'm wrong when proper evidence shows that I'm wrong. I have never claimed to be infallible (which is something an egomaniac WOULD do :). 



This is for anyone reading this, not just Carl:

If you are interested in getting into astro, the kind of equipment you've mentioned is pretty costly. For one, once you get into the realm of cooled CCD imagers, your into the realm of buying each piece individually. You need a mount, a scope, an imager (and all the related accessories), as well as the appropriate guiding equipment (unless you REALLY go all-in on the mount). And you need the kind of quality equipment that will allow you to take full advantage of a cooled CCD imager.

(...bleh, I'm re-stacking my image, and it's sucking up all my cpu....letters are trickling onto my screen at a rate of about 1-2 every second...)

A really low end CCD imager might cost you a few hundred bucks. A single-stage cooled CCD is going to be around a grand, however single-stage doesn't always cut it...it can't always combat ambient temperature well enough to maintain a constant temperature, which is really what it boils down to. You don't just want cold, you want constant cold. For that, you need a two-stage TEC system, and that bumps the cost up to around $3000. Once you move into the realm of cooled CCDs though, most of those are monochrome. That means you need a filter wheel. Those can cost a couple grand themselves, especially the ones with pre-filter off-axis autoguiding capabilities. The autoguider itself is likely to cost another grant. So were talking about $5000 to $7000 for a midrange 2-stage peltier-cooled CCD camera with filter ring and off-axis guider. 

If you really want to go balls-to-the-walls, you can pick up either a full-frame CCD sensor (same 36x24mm size as FF DSLRs) or a large 4096x4096 square imager. These tend to run somewhere between $10k and $45k. Some of the larger square sensors use three-stage cooling with an additional watercooled option for the third stage. The sensors of the highest end models are often medium format sized. Pixel sizes can be as large as 9µm!

As for the scope, there are a hell of a lot of options. You can pick up an Astro-Tech 6" Ritchey-Chretien Astrograph for about $400. That is the same aperture diameter as my 600mm lens, however the f-ratio is f/9, rather than f/4. That is more than two stops, meaning you need exposures at least four times as long. My image above was done with 180 second (3 minute) exposures. You would need to go full 10 minute (600 second) exposures with the AT6RC. Getting longer exposures like that requires not only good equipment, but you also have to align that equipment extremely, extremely well (and it's best to use an off-axis guider (OAG). 

You can get a cheap OAG like Orion's and use it with an SSAG, and you might spend less than $1000, but since were talking cooled CCD imaging, your probably in the $5000-$7000 CCD range now anyway. You really want a better OTA than the AT6RC to take full advantage of that fancy imager. There are larger scopes that will do the job. The Celestron EdgeHD 11" is one of them. It clocks in at around $3300, just for the OTA. It needs a mount capable of handling at least 40lb capacity (80lb with weights.) The Astro-Tech 12" Ritchey-Chretien Truss, a newly released truss-type cassegrain, runs for about $4500. It's the cheapest truss astrograph on the market, and uses the Ritchey-Chretien design used in all the huge multi-meter cassegrain type scopes in professional and university observatories. 

You can also move to the next step up, the AT16RC Truss, which runs about $7000. Now with a scope like this, your into the realm where you can really take FULL advantage of a cooled CCD imager. The Truss design handles issues like flexure very well. It reduces weight, since you don't have a closed tube consuming materials. The open design eliminates temperature issues...as the air cools, you don't have to deal with a temperature gradient between outside and inside air. This reduces extraneous sources of tracking imperfections that affect the stability of your stars and their position on the sensor for longer exposures. 

Beyond the AT16RC Truss, you move into the realm of RCOS and PlaneWave scopes. They also use the truss design, RCOS uses Ritchey-Chretien (RC) type mirror design while PlaneWave uses the Corrected Dall-Kirkham (CDK) type mirror design. These are the top two mirror designs for high end scopes, and they both have their strengths and weaknesses, however PlaneWave's CDK design seems to produce some of the best on and off-axis spots in the market. For wide-field imaging (where you don't intend to crop, rather you intend to use every square pixel of every image that comes out of the scope), where corner performance is just as critical as center performance, RCOS and PlaneWave are the best choices, as they offer some of the best off-axis performance on the market. You pay for it, however...as these scopes tend to START at around $15,000, and can be as high as $200,000.

Finally, you need a mount that will support your equipment. Working backwards from the high end, you have ASA mounts, Astro-Physics mounts, Software Bisque's Paramount, and 10Micron mounts. These all cost about $10,000 for the low end, and as much as $50,000 for the high end. They can handle scope capacities of 100lb to several hundred pounds (which is often the case with the larger RCOS and PlaneWave scopes.) ASA makes some of the most precise and accurate mounts in the world. The lowest end mount from ASA that might handle a PlaneWave is about $20,000. Their mounts have an intrinsic error rate that is less than 1" (one arcsecond), lower than any mount from any manufacturer listed. Mounts from Astro-Physics, Paramount, and 10Micron cost about the same, and offer similar performance (although most require periodic error control or PEC to be programmed and enabled first, or the addition of absolute encoders, which greatly increases cost). 10Micron mounts are a nice middle-ground. They always come with built-in absolute encoders, so they offer not only high tracking accuracy and precision, but they can also compensate for issues like wind, or can pick up exactly where they left off if there is a power loss (most other mounts must first "sync to home"). If your using an RCOS or PlaneWave, you are going to be using one of these mounts.

The next step down would be the high end of the midrange mounts. This is the Celestron CGE Pro and the Meade LX850. These mounts are not as precise as the top end mounts listed above, but they will give you good tracking accuracy, and with PEC offer precision under 2". They both offer sync to home behavior, so if your using bigger equipment (i.e. scopes larger than 9-10") that need a more "permanent" installation, they are the cheapest options that meet the criteria. They can handle scopes and other equipment weighing up to 90lb. These mounts cost about $5000. Astro-Physics also offers a $7000 mount called the Mach 1 that offers most of their high end quality and precision, however it is only capable of handling 45lb of scope and accessory weight, so it is often not an option for larger scopes. It'll handle the Celestron EdgeHD 9.25 or AT8RC well enough.

The mainstream mounts that most amateur astrophotographers use are the Celestron CGEM, Orion Sirius and Atlas, SkyWatcher EQ-6, and iOptron iEQ45 and ZEQ25 (and probably the forthcoming CEM60). These mounts cost in the range of $1000 to $3000, and usually have capacities ranging from 20lb to 60lb. They can handle most of the entry-level and midrange scopes, including things like Celestron's EdgeHD 9.25" and even EdgeHD 11", AT6RC, AT8RC, maybe AT10RC, Meade's counterparts to Celestrons EdgeHD scopes, etc. They will also handle most of the refracting scopes on the market with the exception of a few, such as Officina Stellare's larger refractors (and probably most of their reflectors.)

So, you have three major brackets of equipment that would work for cooled CCD imaging...low end, midrange, and high end. You can probably split midrange and high end into two sub brackets:

*Low End (for astrophotography):*

$1000 Orion Sirius EQ-G Mount
$400 Astro-Tech 6" Ritchey-Chretien OTA
$1200 Atik 420C Color CCD (cooled, ~30°C Delta-T)
$425 Orion SSAG 50mm Mini Autoguider 
-------
$3,025

*Lower Midrange:*

$1500 Celestron CGEM or Orion Atlas EQ-G Mount 
OR
$3000 iOptron CEM60
$1300 Celestron EdgeHD 8" OTA
$4300 SBIG STF-8300 Mono + 5 slot Filter Wheel (remote controllable) + LRGB color filters + OAG (cooled ~50°C Delta-T)
--------
$7,100-$8,600

*Higher Midrange:*

$5000 Celestron CGE Pro or Meade LX850 Mount
$4500 Astro-Tech 12" RC Truss OTA
OR
$7000 Astro-Tech 16" RC Truss OTA
$5500 SBIG STT-8300 Mono + 7 slot Filter Wheel
$950 Astrodon LRGB Filters
$725 Astrodon OIII (Oxygen 3) 3nm Narrow Band Filter
$725 Astrodon SII (Sulfur 2) 3nm Narrow Band Filter
$725 Astrodon Ha (Hydrogen-Alpha) 5nm Narrow Band Filter
--------
$18,206 - $20,625

*Lower High End:*

$15000 10Micron 1000HPS or Paramount MX or Astro-Physics 1100GTO
$7000 Astro-Tech 16" RC Truss OTA
$5500 SBIG STT-8300 Mono + 7 slot Filter Wheel
$950 Astrodon LRGB Filters
$725 Astrodon OIII (Oxygen 3) 3nm Narrow Band Filter
$725 Astrodon SII (Sulfur 2) 3nm Narrow Band Filter
$725 Astrodon Ha (Hydrogen-Alpha) 5nm Narrow Band Filter
--------
$30,625

*Ultra High End:*

$33000 10Micron 4000HPS Mount w/ Absolute Encoders
OR
$37000 ASA DDM160 Mount
$50000 24" PlaneWave CDK OTA
$2000 Digital 10 filter Filter Wheel
$800 MoonLite CSL 2.5 inch Large Format Crayford SCT/RC Focuser w/ digital motor & accessories
$35000 Cooled Kodak KAF-16801 CCD, ~65°C Delta-T, 16mp 9µm 4096x4096 37x37mm sensor [Many manufacturers use this sensor, SBIG, FLI, etc.]
OR
$37000 FLI Cooled E2V CCD42-40 Back-Illuminated, ~65°C Delta-T, 4.2mp 13.5µm 2048x2048 28x28mm sensor
OR
$37000 FLI ProLine Kodak KAF-4301E Class 1 CCD, ~65°C Delta-T, 4.3mp 24µm 2048x2048 50x50mm sensor
$950 Astrodon LRGB Filters
$950 Astrodon OIII (Oxygen 3) 3nm Narrow Band Filter
$950 Astrodon SII (Sulfur 2) 3nm Narrow Band Filter
$950 Astrodon Ha (Hydrogen-Alpha) 5nm Narrow Band Filter
$950 Astrodon Ha 3nm Narrow Band Filter 
----------
$125,550 - $131,550


----------



## jrista (Feb 28, 2014)

*Re: Deep Sky Astrophotography*

With the low end rig, you are going to have a tough time getting the kind of image I did, not because I'm good (I'm not.) You need to very precisely align and calibrate your mount to be able to track accurately for a long time, because of the small aperture. You would need to be able to track stars for at least 10 minutes without "drift" (something you can correct for with drift alignment, a painstaking process). You really wouldn't be taking advantage of a cooled CCD there, so I really would just recommend using a DSLR. Save you some money (especially if you already have a DSLR). Use an Astronomik CLS filter with Canon DSLRs, and you can even shoot under the light polluted skies of the city. 

Once you get more serious than a $400 OTA and a DSLR, you can move up the line to higher and higher grade setups. It starts getting more expensive once you get into monochrome CCD territory, because you _have _to use filtration. (Unless your just interested in pure monochrome imaging, some people do that.) Filters for astro are like filters for normal photography...you get what you pay for. Astrodon and Baader Planetarium make some of the best filters. At the very least, you would need LRGB filtration to use a mono CCD. If you live under light polluted skies, narrow band is the better option, as it cuts out ALL of the pollutant light, however narrow band imaging is much tougher...you still need very precisely aligned equipment, and you need to expose for at least 10 minutes, often as much as 20-30 minutes. Generally speaking, a CGE Pro or LS850 are BARELY going to get you more than 10 minutes unless you have exceptional skill at aligning. You need to move up to the high end mounts, especially those with absolute encoders, to really get the kind of tracking necessary for good narrow band imaging. Narrow band is a lot tougher to process in post as well...you have to do something called mapped color, where you map the SII, Ha, and OIII wavelengths to the red, green, and blue channels. But it isn't really just that simple, you have to make sure the images blend smoothly into each other...it's pretty advanced stuff, but the results are truly amazing. 

If you move beyond 8-9.25" scopes or medium sized refractors (refractors are good, but these days generally don't have nearly the aperture of reflectors, or they do, it's just ultra costly, similar cost to the 600mm f/4 L II lens), then your really looking at a "permanent" setup. You are then either planning to build an observatory on your property, or build or rent one at a remote location like New Mexico Skies, where you can have remote computer control and high end robotic mounts (Paramount, ASA, 10Micron, Astro-Physics) under skies that are always dark, always away from light polluted cities. This is what a lot of serious amateur astrophotographers do, though...you would be surprised how many have about $20k to $30k in equipment and have built their own observatories on their land. All things considered, if your serious about normal photography, like wildlife or sports, you've probably spent about that much on your photography equipment (I know I've spent a little over $20k on my photography equipment.) So, while it sounds like a lot...it actually isn't all that much more than most people spend on their hobbies anyways (and, in many respects, a LOT cheaper than many hobbies...some people spend hundreds of grand on their "Fix up that old muscle car" hobby or their watersports hobby or whatever.) You can also kind of work your way up there as well. If you start with a really good mount, like the Astro-Physics Mach 1 or the iOptron CEM60, you have a very good mount that will last you for a very long time, and support most of the OTAs you might use (until you get up above the 10" cassegrain range...then you'll need something larger than a Mach 1). 

There is another option for those who already own good normal photography equipment. The Canon L-series telephoto lenses make EXCELLENT telescopes. They rival high quality refractors like the Officina Stellare Hiper APO 152, which is a 6" (152mm) aperture just like the EF 600mm f/4 L II. The Hiper APO 152 costs about the same as well. Pretty much any Canon great white L-series telephoto can do the job, the old Mark I generation as well as the Mark II. You need to either get some custom parallax rings built to hold the lens into your mount, or get some ADM saddles and dovetail plates to bolt the tripod foot to your telescope. Along with some guiding equipment and a good midrange mount like the Orion Atlas EQ-G, and you have yourself a very high end setup capable of taking some amazing images. 

The most popular lens to do this with, it seems, is the EF 400mm f/2.8 L Mark I. It's relatively cost effective, relatively long, has an ultra wide aperture so slapping on the 1.4x and 2x TCs gets you 640mm and 800mm focal lengths, which give you a good range with which to do moderately wide field astrophotography. (If you really want to use the 2x TC, it's best to go with the Mark II generation than the Mark I, but either will still do...the Mark I will just not be quite as pinpoint sharp, and will suffer from aberrations in the corners of the field.) The ADM saddle parts and necessary dovetail parts might cost around $350-$500. A basic guide scope, the Orion SSAG Magnificent Mini Autoguider, costs about $425. Along with the $1500 mount, and you have youself a pretty high grade astrograph setup. Obviously, this assumes you already have one of Canon's great white lenses...but with so many wildlife photographers around, that isn't all that unusual.

Even if you don't have a Great White lens, if all you have is a 70-200mm and a Canon 550D, you can still actually do quite a bit of astrophotography. You will need a good mount, the Orion Sirius EQ-G is a good place to start, however if you think you might eventually want to move up to a 6" or 8" scope, you should get the Orion Atlas EQ-G. You can mount the camera onto a V-type dovetail plate, which clamps into the saddle on the mount. Once you polar align the mount, you can then use the mount's hand controller and GOTO system to point your camera at anything in the night sky. You can then either just use a normal remote shutter release and bulb mode to take exposures...and they could be very long, up to a few minutes even (without guiding, much longer with guiding). You would be blown away at what a good old 85mm or 50mm or 24mm prime can do for you on a tracking mount. Those are your ultra wide field lenses, and they capture either the whole sky, or constellation-sized regions. The 70-200mm lenses and 135mm lens are also excellent for wide field work, although not quite full-constellation size. At 200mm you can zero in on just the Orion Belt and Sword region of the Orion constellation, for example. If you have a 400mm lens you can zero in on just the belt. If you have something like the Tamron 150-600, you can zero in on just the horse head and flame nebula region in the belt or just the Orion nebula region in the sword.

You can do a hell of a lot with just a lowly Canon DSLR, your existing lenses, and a $1000 tracking mount. At the very least, it's a place to start before you begin working your way up to that awesome $30,000 rig!


----------



## CarlTN (Feb 28, 2014)

*Re: Deep Sky Astrophotography*

Having not even read all of that yet, and doubt I will tonight...let me just say that, I think you knew I was being sarcastic, because that actually is really what I think of you. And I know you think even worse of me, so I know you were also being sarcastic. But it's kind of fun to not let our personal mutual disgust get in the way of other important things such as photography.

I also wanted to say that, having not thought much about what I asked above (apparently), I can answer my own question with a simple answer (as in, why not get a scope instead, etc.).

(Besides the fact that you are a birder)...It's because you want a wider field of view than most telescopes provide, correct? I'm pretty sure most of the astro images I've seen, that needed a wider field of view, were not shot with telescopes, but rather SLR cameras and lenses.

Ok, I read some of the end of one of your posts. 9 micro meters for a pixel on a medium format imager...impressive. Would you happen to know what sort of imagers some of the well known observatories use? I'm sure it's probably customized, or "bespoke" componentry, but was just curious. I imagine the sensor is even larger than medium format. The one in the Hubble Space Telescope I assume, is quite large, but probably not the largest. Perhaps the "wide field" space scope uses an even larger imager (the one that hunts extra-solar planets, detects phase shifts from stars)...I think this is not even really called an imager, is it?


----------



## jrista (Feb 28, 2014)

*Re: Deep Sky Astrophotography*

The Pleiades. The first few frames I managed to get on the first night I set up my telescope setup:







This was stacked from only a few frames, maybe 28. I had originally intended to take about 100 frames or so, but cloud cover and an accidental unplugging of my power cable ended up ending the night before it really got started.


----------



## jrista (Feb 28, 2014)

*Re: Deep Sky Astrophotography*



CarlTN said:


> Having not even read all of that yet, and doubt I will tonight...let me just say that, I think you knew I was being sarcastic, because that actually is really what I think of you. And I know you think even worse of me, so I know you were also being sarcastic. But it's kind of fun to not let our personal mutual disgust get in the way of other important things such as photography.
> 
> I also wanted to say that, having not thought much about what I asked above (apparently), I can answer my own question with a simple answer (as in, why not get a scope instead, etc.).
> 
> (Besides the fact that you are a birder)...It's because you want a wider field of view than most telescopes provide, correct? I'm pretty sure most of the astro images I've seen, that needed a wider field of view, were not shot with telescopes, but rather SLR cameras and lenses.



There are some very good short focal length refractors out there specifically designed for wide field work. There is also the HyperStar option for Celestron SCT scopes, which focal reduces them to f/2 instruments. If you have a 2800mm f/10 11" EdgeHD, and convert it with Hyperstar, you now have a 560mm f/2 imager...that is an even wider field than I get with my 600mm. Some refractors are as short as 400mm. 

I think a lot of people DO use their camera lenses for very wide field work, for sure....although I think that is more a matter of convenience than anything. A good apochromatic 80mm f/4 scope (320mm focal length) can cost a pretty penny (several thousand), where as a 300mm f/4 camera lens might cost $1000 cheaper (although can still cost a thousand or two itself.) The actual apo 80mm f/4 refractor will be a much better device for imaging, and if y our serious about your astrophotography, it's the better route to go for wide field work (unless your talking Canon Great White telephotos, in which case until you get to the real high end range of apo scopes, the Canon lenses will be better.)

There are actually some professional scientific groups that use arrays of Canon lenses to do deep sky imaging. I know that EF 200mm f/1.8 L and f/2 L, EF 300mm f/2.8 L, EF 400mm f/2.8 L lenses have all been used in ultra fast (i.e. f/1!) telescopic arrays. Some have been used to find ultra dim deep field objects (super distant, dim galaxies), others have been used to find the dimmest nebula and galactic disc detail ever (the size of the average galaxy, according to some papers about an array that uses 12 EF 400mm f/2.8 L lenses in an f/1 setup, is significantly larger than is normally seen in your average visible light imaging...at f/1, you can gather so much light that you can see the dimmest structures in the universe with the exception of what Hubble itself sees.) 



CarlTN said:


> Ok, I read some of the end of one of your posts. 9 micro meters for a pixel on a medium format imager...impressive. Would you happen to know what sort of imagers some of the well known observatories use? I'm sure it's probably customized, or "bespoke" componentry, but was just curious. I imagine the sensor is even larger than medium format. The one in the Hubble Space Telescope I assume, is quite large, but probably not the largest. Perhaps the "wide field" space scope uses an even larger imager (the one that hunts extra-solar planets, detects phase shifts from stars)...I think this is not even really called an imager, is it?



Hubble has some large imagers, but its newer and more advanced ones are not all that large. Certainly not the largest.

A lot of professional observatories use PlaneWave scopes on Paramount ME II mounts with FLI imagers as the lowest end imagers they might use. There are some much larger imagers out there. Some have diagonals as large as 90mm, which is utterly massive, that's a 64mmx64mm sensor. These sensors also tend to have around 70dB of dynamic range. When you factor in a multi-stage watercooled TEC with a 70°C to 80°C Delta-T and read noise levels in the 0.001e- range, and they utterly blow the crap out of your average DSLR sensor or even a cooled $10,000 astro CCD imager. Imagers like that tend to cost a hundred grand a piece. 

The larger PlaneWave scopes, including the $200,000 28", have become pretty standard these days for professional installations. They are usually set up as arrays and calibrated to point at the same locations in the sky synchronously. So, you might have an array of five PlaneWave 28" CDKs all with the high end 65mm or 90mm (diagonal) sensors. Your average multi-scope array setup for a university probably costs a couple million bucks, but in terms of combined relative aperture and sensitivity, such a setup can rival a mountain top observatory for total light gathering capacity, at a tenth the cost or less. 

The largest telescopes on earth, like the Keck 10 meter, is an f/1.74 monstrosity. The Keck observatory houses multiple scopes, uses active optics, and dozens of imaging devices. I doubt any branded cameras were used...they probably use sensors from Teledyne, E2V, etc. and built them directly into the system.


----------



## jrista (Mar 1, 2014)

*Re: Deep Sky Astrophotography*

Someone asked about the specifics of my exact setup, as they use a 500mm f/4 lens. Here they are, for those who are interested in getting started the same way I have:






*HARDWARE*

*Mount:*
Orion Atlas EQ-G | $1499

The mount is the most important part, hands down. Unless your going to dive head first into scopes larger than 11", you should be looking at the Celestron CGEM or the Orion Atlas EQ-G. I did a lot of research, spent almost a month on it. Celestron mounts are quite pretty, and they are actually manufactured by the same company that manufactures the Orion Atlas (which is the same as the Skywatcher EQ-6). Since it's introduction, however, the Celestron CGEM (and slightly larger sibling CGEM DX) has had some intrinsic gearbox problems, as well as a gear cogging problem. Celestron has done a couple things to fix these issues, however the gearbox is pretty fundamental to the design of the mount. There seem to be no real solution to the issue, which introduces a source of non-periodic error (or rather, periodic error, but at a different cyclic rate than the standard worm gear causes, and when the two converge & diverge, it creates a problem for autoguiding.) 

The Orion Atlas is a very good mount. Feature wise, it's a bit better than the Celestron CGEM. It comes with a "dual" saddle built in. There are two main types of dovetails used with astronomy gear: The V-type or Vixen, and the D-type or Losmandy. D-type is much larger, much more stable, than V-type, and is essential for larger gear (like a 500mm f/4 lens.) The Orion always comes with a built-in polar finder scope (its situated in the right-ascension axis, and is used to align the mount itself with the exact celestial pole.) The polar finder scope is an add-on option for Celestron CGEM. The Orion polar finder scope comes with a built-in red LED to help you see the reticule diagram...the Celestron's add-on polar finder does not (although there are guides online that can help you solder in your own onto the mounts control board, if your up for it.) 

The really nice thing about the Orion Atlas mount is that there is a good, high quality belt drive for it. Belt drives are what the higher end scopes use. Direct Belt Drive is what the ASA DDM (Direct Drive Mount) line of mounts use, and part of why they have exceptional accuracy and practically no problems with gear backlash. The existence of this upgrade (it costs a couple hundred) is one of the key reasons I purchased an Orion Atlas. I will be adding this upgrade in the future...from what I hear, it greatly smooths out the tracking and allows it to be more precise, with and without guiding. There are also other upgrades for the Orion Atlas, as well as a service called "HyperTuning" offered by DeepSpaceProducts (hypertuning is also available for the CGEM.) 

My recommendation is to definitely get the Orion Atlas. When you get the atlas, also search for and buy an "EQDIR" adapter. EQDIR is a special TTL connecting cable that allows you to plug your computer directly into the mount, and control it with software called EQMOD. EQMOD is another bonus for the Orion Atlas that the CGEM does not have...very powerful, very capable software that can do everything the hand controller does, and much more. It also allows "plate solving"...more on that in a bit. (The EQDIR cable costs about $40.) 

*Saddle:*
ADM D-series Side-by-side "Dual" | $249

ADM makes a number of accessories for astronomy equipment. I purchased the DSBS "Dual", or D-type side-by-side "dual saddle" model adapter so I could mount both my lens+camera as the "telescope", and also use an external automatic guiding setup with it's own lens. I'll get into that in a bit.

There are a number of saddle options, and a number of sbs saddle options. You can get V-type or D-type, or dual which takes both vixen and losmandy dovetails. I chose the dual, so that I would never have to spend more money adapting anything to my mount. It's $50 more expensive, but ultimately, it is going to be worth it, because it gives you more freedom to expand in the future. At longer focal length telescopes, you inevitably need larger guiding scopes. 

*Dovetail:*
Astro-Tech Losmandy Style 7.9" | $50

I purchased this dovetail plate to attach my 600mm f/4 lens to the ADM DSBS saddle. There are a bunch of dovetail plates on the market. The nice thing about this one is that it has a slot down the middle, rather than a set of pre-spaced holes. The slot is essential to properly attaching your lens to the plate. With other dovetails, you are stuck either sinking your own hole for the second screw, or using a single screw...and THAT is bad news...one screw will not cut it, because as the mount moves the scope to track across the sky, its angle can change considerably...once it gets to a point where it is more parallel to the ground, a lens bolted to the plate with a single screw will easily slip...and that can potentially cause the whole entire setup, mount and all, crashing to the ground. On top of your lens. The overall weight of the entire setup is about 70 pounds...not even a Canon Great White lens would survive that.

Get this dovetail. Then, go to your hardware store, and buy some 1/4"-20 hex head screws with the small round heads that are about 1/2" long. The hex head ones with a small round head are important, because anything else is generally too large to fit into the slot on this dovetail, and will not hold the lens to the plate securely enough. Use those to bolt the dovetail to BOTH screw holes on your lens' foot. 

*Guider:*
Orion SSAG w/ 50mm Mini Guidescope | $349

For a starter guiding package, you really can't go wrong with the Orion 50mm Mini Guidescope and the Orion SSAG (StarShoot AutoGuider). Don't get roped in by the "delux" version of this, which is about $70 more. All that ads is a helical focusing ring on the scope, however the scope can already be focused in two ways: Either by unlocking the front part that holds the objective and rotating it, then locking it again. Or by sliding the SSAG mini guider (which is really just a webcam sensor packaged with a logic chip that can control your mount through what is called an ST-4 port) in and out of the other end until your focused, then locking it down. Save yourself the $70, just get the Orion SSAG with 50mm Mini scope for $349. 

There are other guiding options out there. The only other one I think is worth while is the SBIG ST-i guider. The SBIG is a higher quality guider, nice and compact, however it is a lot more expensive. Between a scope and the guider itself, you'll probably spend $800. The ST-i is really the option you want to go with if you eventually move to a full blown cooled CCD camera. The SBIG STF-8300M is a great midrange peltier-cooled mono astro cam, and in a package deal, you can get the cam, a filter wheel, as well as an OAG (off-axis guider) adapter that the ST-i plugs into. Off-axis guiding is generally more effective than external guiding, as it observes the sky through the same optical tube your imaging through. That allows it to correct for things like flexure. Flexure is one of the bigger problems with getting very precise guiding (essential at longer focal lengths, not really a problem at 200-1000mm). Flexure is the flexing...the bending and twisting...of an OTA (optical telescope assembly) as it is moved by the mount during tracking. It can result in elongation and wobble of stars that makes them look "unnatural" and "not round". 

If you think your really going to get into astrophotography, and figure you'll eventually get a proper telescope (i.e. a Newtonian, SCT, or RC), then you might want to start with the ST-i. You can still attach it to an external guide scope (any smaller refracting telescope will work, or even the Orion 50mm mini guidescope).

*Misc:*
AC Power adapter for your DSLR (for use when your at home)
DC power adapter for your DSLR (for use with a deep cycle battery when your at a "dark sky" site)
DC power adapter for your laptop (for use with deep cycle battery ...)
2-3x DC cigarette plug with positive/negative clamps (for use with deep cycle battery...)
A 20-30 Ah deep cycle battery to power the mount at dark sky sites
A 100 Ah or larger deep cycle battery to power your camera and laptop

*SOFTWARE*

In order to effectively use the equipment above, you need the proper software. You need control software to actually control the camera and any other accessories (such as focusers and filter wheels, of your using them). You need stacking software. You need processing software. You will also need guiding software to make guiding actually work. Finally you will need planetarium software to tell the mount to point at various things in the sky.

*Control Software:*
BackyardEOS
Nebulosity
Sequence Generator Pro
MaxIm DL

Control software connects to the camera at the very least, possibly multiple accessories like a motorized focuser, robotic filter wheel, and even the mount. You use control software to frame, focus, and set up sequences for imaging. Imaging sequences can be light frames (i.e. 30x240s f/4 ISO 400 with lens cap off), dark frames and bias frames (with lens cap on), and flat & dark flat frames. Certain objects in the sky are exceptionally high dynamic range. Orion Nebula is the best example. Sometimes you need very long exposures, medium exposures, short exposures, and very short exposures, to fully capture the dynamic range. But in astro imaging, each "exposure" is ultimately an integration...a calibrated ((light frame - dark frame - bias frame) / (flat frame - dark frame)) image stack. So for each of those groups of integrations, you have multiple individual light frames, as well as the corresponding dark frames. You don't just take an image and then be done, like you would with normal photography. You can potentially take hundreds of individual frames of the same object, often over the course of several nights, just to make ONE image in the end. 

Control software is essential. It takes a LOT of the tedium out of the process. Largely personal preference. I highly recommend looking into BackyardEOS and Sequence Generator Pro.

*Guiding Software:*
PHD2

In order to guide, you need guiding software. There is really only one option here, PHD2. MaxIm DL, the control software above, also supports guiding, but PHD2 is free and its the de-facto standard. It's highly capable, very easy (the acronym literally stands for "Push Here Dummy"!), and, free. 

*Stacking Software:*
DeepSkyStacker
AstroStack
RegiStax
Images Plus
IRIS
[many others]

Stacking software is the first step in the post-processing stage. You bring in all your light, dark, bias, flat and dark flat frames. You configure the application for stacking. You register, then you stack. Sometimes the last two are part of the same step. Once stacked, you export an unmodified 32-bit TIFF, and your ready for the next step.

DSS, or DeepSkyStacker, is easy and free. Probably best to start there. There are a bunch of options here, with different capabilities for different purposes. Some are better for planetary stacking, some are better for galaxy and nebula stacking. Experiment. 

*Processing Software:*
Adobe Photoshop 
PixInsight

Processing software is what you use to "stretch" your integrations. Calibrating and stacking images into a single integration GREATLY reduces noise, and enhances dynamic range. If you understood the kind of noise levels and dynamic range levels that are fairly common in astrophotography, even the much vaunted 14-stops of DR that you get with a D800 would make you laugh at how pathetic that is!  With a DSLR and a proper stack of dozens or even a hundred deeply exposed frames (several hundred seconds at least), along with dark, bias, and flat calibration, you can have well more than 14 stops of DR. If you were using a multi-stage cooled CCD imager, where dark current noise is in the 0.1e- or less range, after stacking your dynamic range from the darkest bits of dark nebula to the brightest pinpoint peaks of stars could be as much as 20 stops of DR, maybe even more (in which case, your most definitely using 32-bit float TIFF images, which are capable of storing what is effectively unlimited dynamic range, at least for the purposes of mankinds endeavors. )

Photoshop is pretty much a given. It's the staple of image processors, for everything. If you are a photographer and do not have PHOTOshop, then your a twit. Get it. You need it.  There are thousands of tutorials, video and article, on the net that cover using Photoshop for processing astro images. There are bunches of PS actions for free and for sale that take care of common tasks that are just essential parts of stretching and enhancing astro images. You really can't do astrophotography without it.

PixInsight is the big 800 pound gorilla when it comes to editing astro images. It brings to the table a whole, broad range of mathematical tools that allow you to process your images in ways Photoshop could never even tough, using advanced algorithms that can deal with noise in ways you never even imagined, extract detail from the black background depths that are so deep you wouldn't have even imagined that you could imagine there being detail there at all. It even offers "pixel math", giving you the ability to apply any kind of algorithm you can imagine to your images, effectively allowing an infinite amount of ways to process, calibrate, color balance, stretch, extract, and otherwise enhance your images. Oh, and beware...it has a REALLY _*balls-to-the-walls on-crack brain-melding kind of wacked out UI design*_ that will totally make you go BONKERS for the first few days...but that eventually passes. 

Nothing beats PixInsight for astro editing. But you still need Photoshop, because there are still some things Photoshop just does better. You need both of these. (But start with Photoshop.)


----------



## jrista (Mar 1, 2014)

*Re: Deep Sky Astrophotography*

Close-up crop of Flame, Horse Head, IC2023:


----------



## CarlTN (Mar 1, 2014)

*Re: Deep Sky Astrophotography*

Thank you for all the details, very interesting and impressive! I must say, the most interesting part from the perspective of photography and photo lenses, is the arrays of them you are talking about. How does that work? Do they each feed their own imager that is then digitally summed somehow, or is it mechanical, using prisms or some kind of mirrors to reflect it all into one imager?


----------



## CarlTN (Mar 1, 2014)

*Re: Deep Sky Astrophotography*



jrista said:


> The Pleiades. The first few frames I managed to get on the first night I set up my telescope setup:
> 
> 
> 
> ...



Nice, so this was with the 600mm Canon lens and the 7D?


----------



## scyrene (Mar 1, 2014)

*Re: Deep Sky Astrophotography*

This has all been very interesting and informative! But I'll stick with my plan - my budget just doesn't stretch that far! I think living in a country where the weather is unreliable, many nights ruined by cloud - and not having access to a very dark site - means it wouldn't be worth bothering with high end equipment. Mind you, it's amazing what can be done without telescopes, cooled sensors, etc.

Fwiw my roadmap goes: full frame in-body light pollution filter (just out, though not available yet) ~£130, better tracker ~£500 (minus what I can get back by selling my current one).

The latter should allow me to use the 500mm f/4 for tracked astro work at last, and that should keep me happy until midsummer, when the nights are too short here to be able to do any night sky photography. Come autumn, maybe there'll be room for another upgrade


----------



## jrista (Mar 1, 2014)

*Re: Deep Sky Astrophotography*

Oh, I forgot about planetarium software and plate solving. You will need that as well:

*Planetarium Software:*
Microsoft WorldWide Telescope
Stellarium
Cartes du Ciel
[others]

Planetarium software allows you to find things in the night sky to observe or image, and can be used to instruct the mount to go to (point the scope to) those objects. By far the easiest way to navigate the sky is with a planetarium. 

I personally use Microsoft WWT. If offers a full color ultra high detail seamless map of the sky made from actual photographic images, and offers very fluid and smooth panning, zooming, tracking, etc. It has a very useful search tool. It can connect to your mount directly. 

Largely a matter of taste, however. 

*Plate Solving:*
AstroTortilla
Elbrus
Pinpoint
(SGP)*

Plate solving is a process by which an image of the sky is "solved", or where all the stars and other celestial objects are identified by matching it to an index of the sky. Plate solving allows the control software on your computer to know exactly where your mount is actually pointing. There is usually some amount of residual error in pointing, so when you tell the mount to point to "IC434" or "M45", it may not actually center that object in the view. When it comes to brighter objects, that isn't such a huge problem, you can "star hop" until you find the object visually. 

For dimmer objects, it's impossible to see them unless you have a telescope with a HUGE aperture (i.e. 14" or more) and a large eyepiece...however with astrophotography, you generally don't have eyepieces and often don't have large apertures, and only computer control software with which to find things by. Accurate pointing is then quite important. By plate solving, you can automate the process of working out the error in your pointing. AstroTortilla is the simplest way to start plate solving. It's free, simple, and effective...once you get it configured right (you MUST learn how to set the min and max scaling, scale factor, and sigma values for your actual FoV of the sky with whatever lens or scope you are using in order for it to work.) AT will work with other control software like BackyardEOS, SGP, MaxIm DL to automatically take images of whatever the telescope is pointing at, solve the image, use the information about the exact region of the sky that image indicates the mount is pointing at to "sync" with the scope a new, more accurate model of the sky, and repoint. The process can automatically be repeated until your pointing accuracy is within a certain configurable precision...by default 1" (one arcsecond). After this, you should be able to point to anything on that side of the meridian (the imaginary line that goes directly overhead from north to south that divides the sky into eastern and western halves). After a meridian flip (the necessary action when an object starting in the east moves past the meridian, where the mount is reoriented in the opposite configuration to point at objects on the western side of the sky), you may need to plate solve again for pointing accuracy to be perfect again. 

For fully automated imaging, you can use Sequence Generator Pro (SGP). SGP supports automatic meridian flipping and integrates plate solving to support highly accurate, fully automated all-night imaging. Without plate solving, due to the often inherent error in mount+telescope setup (called cone error, where the optical axis is not exactly at a 90° right angle to the declination axis), pointing accuracy is often off by a few minutes RA/degree or two Dec after a meridian flip. This requires meridian flips to be manual, and if you are not paying close attention to the imaging process, a meridian flip can cost you time. SGP can detect when the mount is in a "past meridian" point from the east, pause your imaging sequence, automatically do a meridian flip, plate solve and remodel the sky, repoint EXACTLY at your object (not just point, but frame it the same as well), and automatically resume your imaging sequence. 

*Drivers:*
ASCOM

In order for you to be able to properly control your telescope and mount setup from a computer, you will need ASCOM. This is the standard component object model and driver platform that ALL telescope equipment and software use to communicate with each other. You will need ASCOM, and an ascom telescope driver. If you use an Orion Atlas and EQMOD, EQMOD includes an ASCOM compatible driver.


----------



## jrista (Mar 1, 2014)

*Re: Deep Sky Astrophotography*



scyrene said:


> This has all been very interesting and informative! But I'll stick with my plan - my budget just doesn't stretch that far! I think living in a country where the weather is unreliable, many nights ruined by cloud - and not having access to a very dark site - means it wouldn't be worth bothering with high end equipment. Mind you, it's amazing what can be done without telescopes, cooled sensors, etc.
> 
> Fwiw my roadmap goes: full frame in-body light pollution filter (just out, though not available yet) ~£130, better tracker ~£500 (minus what I can get back by selling my current one).
> 
> The latter should allow me to use the 500mm f/4 for tracked astro work at last, and that should keep me happy until midsummer, when the nights are too short here to be able to do any night sky photography. Come autumn, maybe there'll be room for another upgrade



At 500mm, you are going to need guiding. You are also going to need a mount that can REALLY handle the load. That's an expensive lens, and relatively heavy. When you throw in the weight of the guider, the weight of the camera and lens, plus the weight of all the cables coming off them, your going to be around 20lb or so. For smooth tracking without any issues or the chance of toppling over, you want a mount that can handle twice the load. You might be able to get away with an Orion Sirius. The Sirius is $1100, and it can hold 30lb. You can usually find those used for $700, maybe a little less. I really wouldn't recommend anything smaller than that for use with your 500mm lens. If you must go cheaper, then the smallest thing I would recommend would be either the Orion SkyView Pro (which runs about $850 new), or the iOptron ZEQ25GT (also $850 new). You can find both for cheaper used (check cloudynights.com and astromart.com). The SkyView Pro can handle 20lb (your cutting it REALLY close with that), and the ZEQ25GT can handle 27lb (close, but probably acceptable.) 

The iOptron mount won't support EQMOD, so it isn't at the top of my list of recommendations. I really highly recommend that you use an Orion mount...either the Sirius or the Atlas. You can find both used for pretty reasonable prices. I've even seen the Atlas mount used for as cheap as $750.


----------



## jrista (Mar 1, 2014)

*Re: Deep Sky Astrophotography*



CarlTN said:


> Thank you for all the details, very interesting and impressive! I must say, the most interesting part from the perspective of photography and photo lenses, is the arrays of them you are talking about. How does that work? Do they each feed their own imager that is then digitally summed somehow, or is it mechanical, using prisms or some kind of mirrors to reflect it all into one imager?



They all have their own imagers. It's all stacked in post the same way, via an averaging algorithm. Median with Kappa-sigma clipping is a common one. Such arrays are usually mounted with custom adapters that allow multiple lenses to be attached to some kind of frame, and the frame itself is then attached to the mount. You can read about one of these, the Dragonfly Array, here: https://dl.dropboxusercontent.com/u/1727159/DFPapers/674875.pdf


----------



## jrista (Mar 1, 2014)

*Re: Deep Sky Astrophotography*



CarlTN said:


> jrista said:
> 
> 
> > The Pleiades. The first few frames I managed to get on the first night I set up my telescope setup:
> ...



Yup!


----------



## Click (Mar 1, 2014)

*Re: Deep Sky Astrophotography*

Very interesting post jrista. Thanks for sharing all this information.

BTW Great pictures.


----------



## jprusa (Mar 1, 2014)

*Re: Deep Sky Astrophotography*



jrista said:


> The Pleiades. The first few frames I managed to get on the first night I set up my telescope setup:
> 
> 
> 
> ...


 Nice Pictures Jon and thanks for all the information.


----------



## scyrene (Mar 2, 2014)

*Re: Deep Sky Astrophotography*



jrista said:


> scyrene said:
> 
> 
> > This has all been very interesting and informative! But I'll stick with my plan - my budget just doesn't stretch that far! I think living in a country where the weather is unreliable, many nights ruined by cloud - and not having access to a very dark site - means it wouldn't be worth bothering with high end equipment. Mind you, it's amazing what can be done without telescopes, cooled sensors, etc.
> ...



I don't understand what you mean by a guider. There's a new iOptron tracker out this spring here, aimed at DSLRs just like my current one. It takes up to 5+3.5kg according to the specs, although I don't know precisely what they mean. I understand what you're saying about extra capacity, but 5kg is enough for my peace of mind. Here's a link: http://www.tringastro.co.uk/ioptron-sky-guider-portable-dslr-imaging-mount-3683-p.asp

As for the others you mention... are they aimed at telescopes? I found aligning my telescope so counterintuitive I gave up, but the mount I use at present seems straightforward.

To be honest, if it cost any more than that, I'd probably give up at this point. It's too niche an area, even though I enjoy it, for me to justify too much dedicated equipment.


----------



## jrista (Mar 2, 2014)

*Re: Deep Sky Astrophotography*




scyrene said:


> jrista said:
> 
> 
> > scyrene said:
> ...



The sky guider might work. It aligns the same way as the other mounts I mentioned, however...you look through a scope built into the mounts RA axis. It really is not counterintuitive, and once you get the hang of it, it is pretty easy and very precise. It does take some time, though.

It does not look like the sky guider is computerized, however. At 500mm, which is like a small refracting telescope, you are going to have a tough time finding objects in the sky. For wider focal lengths, you'll be fine, but 400mm and 500mm, you'll have to spend some time hunting to find the objects you are interested in. Just be aware of that.


----------



## jrista (Mar 5, 2014)

*Re: Deep Sky Astrophotography*

Two more images. Two nights ago, we had a fluke clear sky...forecast showed cloudy at sunset, turned out to be clear from sunset until after midnight. I got some imaging done on a number of objects, including Pleiades again.

This shot of the Pleiades was much more deeply exposed than my first attempt, however I ended up having some problems with my guiding that consumed a lot of the detail present in the nebula. I worked on this image for two days, but because of the guiding issues, I think it's the best I can do without trying again with better subs:






I also imaged two other regions of the sky. Orion slipped behind the trees before I had a change to get any exposure time on M78. So I looked a little higher in the sky, in Gemini. I was first looking for Jellyfish Nebula, but it is extremely dim, and I knew the mount was having problems guiding, which would have destroyed a lot of the nebula detail. So looking around the same area, I found M35 and NGC2158, two open clusters about too moon diameters above Jellyfish:






The color is slightly false...the blue stars of M35 (the larger cluster) should be just a touch paler, and the red stars of NGC2158 should be a little more varied. I have to use a light pollution filter from my back yard, and it blocks out most of the greens, hence the skewed color. 

I also started imaging one of the galaxy clusters in Leo, however by the time I managed to get that sequence started, the clouds had closed in, and I only managed to get 7 subs before Leo was clouded over.

I am hoping to solve my guiding issues next time there is a clear sky. I also have the option of programming PEC, or Periodic Error Correction, in my mount, which can improve tracking accuracy even further. It's complicated, though, so I haven't tried that yet. I think I'll need about five minute exposures to get good light on the galaxies (and "Galaxy Season" is coming up...once Orion sets, the Milky Way is generally out of sight for most of the night, and the constellations that are overhead, like Leo and the Big Dipper, have bunches of galaxies in them. Until late April, early May, about the only interesting things to image are galaxies.)


----------



## CarlTN (Mar 7, 2014)

*Re: Deep Sky Astrophotography*

Nice work. What keeps the stars from blowing out more than this, if the exposures are 5 minutes?


----------



## jrista (Mar 7, 2014)

*Re: Deep Sky Astrophotography*



CarlTN said:


> Nice work. What keeps the stars from blowing out more than this, if the exposures are 5 minutes?



I use a relatively low ISO of 400. A lot of astrophotographers shoot at ISO 800 or 1600 on APS-C cameras (most often, the 18mp Canon APS-C), however that reduces the saturation point to half or one quarter what I usually get at ISO 400. It might make it a little more difficult for me to pull detail out of the shadows, but I prefer my stars not be blown.


----------



## jrista (Mar 7, 2014)

*Re: Deep Sky Astrophotography*

Here is an image of Orion Nebula and Running Man. This is effectively an HDR image, as this region has EXTREMELY high dynamic range. I used 30x120s + 20x60s + 20x30s exposures to capture the ultra bright core detail where the Trapezium open cluster is, (30s and 60s exposures) as well as the dimmer outer regions of the nebula (120s exposures). I'd have liked to get 240s exposures, but Orion had moved behind my trees before I was able to do that. I wasn't even able to capture all of the dimmer dust detail...and for the detail I did capture, there is probably about 20 stops of DR. I'd probably need about 24 stops of DR to capture it all, meaning I'd need several more sequeces at 240s and maybe 480s to really pull out the dark dusty detail (which fills the entire region):





Couple of close ups:





Running Man Nebula and Dark Dust Lane





M43 and Trapezium Core


----------



## Trovador (Mar 7, 2014)

*Re: Deep Sky Astrophotography*



wearle said:


> To all,
> 
> This is not quite deep-sky, but might be "landscape".
> 
> ...



Love this picture, congrats.


----------



## scyrene (Mar 17, 2014)

*Re: Deep Sky Astrophotography*



jrista said:


> scyrene said:
> 
> 
> > jrista said:
> ...



You've been so kind, I hope my last replies didn't seem churlish. It is a pain finding stuff in the sky, but I have done some fixed tripod work with the 500mm lens. Some objects can be found (if they're near obvious asterisms), by hunting back and forth. A pain, but can be worth it - especially as this is a once in a quarter-year sort of endeavour. Actually, it's looking unlikely that I'll be able to devote any time to astro work this side of the summer now, so I can take stock at leisure. Maybe I'll change my mind again


----------



## scyrene (Mar 17, 2014)

*Re: Deep Sky Astrophotography*



jrista said:


> Here is an image of Orion Nebula and Running Man. This is effectively an HDR image, as this region has EXTREMELY high dynamic range. I used 30x120s + 20x60s + 20x30s exposures to capture the ultra bright core detail where the Trapezium open cluster is, (30s and 60s exposures) as well as the dimmer outer regions of the nebula (120s exposures). I'd have liked to get 240s exposures, but Orion had moved behind my trees before I was able to do that. I wasn't even able to capture all of the dimmer dust detail...and for the detail I did capture, there is probably about 20 stops of DR. I'd probably need about 24 stops of DR to capture it all, meaning I'd need several more sequeces at 240s and maybe 480s to really pull out the dark dusty detail (which fills the entire region):
> 
> 
> 
> ...



Excellent work.


----------



## Jack Douglas (Mar 17, 2014)

*Re: Deep Sky Astrophotography*

Not sure I should even open my mouth here as I'm new to this and indeed very uneducated in the subject. I have modified my iOptron skytracker to add rigidity to the base and allow my gimbal head to be mounted on a horizonatal plane. I removed the gimbal swing arm and mounted my 300 X1.4 and was able to get quite good shots with pretty accurate focus. Aligning Polaris was not too much of an issue but it did need tweaking. With the now horizontal orientation of the iOptron base the gimbal worked really well in allowing smooth balanced movement of the lens.

However, last week I tried 300 X2 and found getting focus to be tricky becasue of lens movement due to lack of rigidity. I will try again and then perhaps have to accept that it's impractical. I'm not fully convinced, but obviously what I'm trying to do is not what anyone who is serious about the stars would be willing to accept.

An even bigger problem is my ignorance of where to aim. Also I have not yet tried stacking. I did post a shot in the other thread but I guess it's no longer active, so here's a sample at 420, 30 sec. My remote timer release is in the mail, so that'll help. Otherwise I'm all ears.

Jack


----------



## Rienzphotoz (Mar 18, 2014)

*Re: Deep Sky Astrophotography*



jrista said:


> Here is an image of Orion Nebula and Running Man. This is effectively an HDR image, as this region has EXTREMELY high dynamic range. I used 30x120s + 20x60s + 20x30s exposures to capture the ultra bright core detail where the Trapezium open cluster is, (30s and 60s exposures) as well as the dimmer outer regions of the nebula (120s exposures). I'd have liked to get 240s exposures, but Orion had moved behind my trees before I was able to do that. I wasn't even able to capture all of the dimmer dust detail...and for the detail I did capture, there is probably about 20 stops of DR. I'd probably need about 24 stops of DR to capture it all, meaning I'd need several more sequeces at 240s and maybe 480s to really pull out the dark dusty detail (which fills the entire region):
> 
> 
> 
> ...


Truly MAGNIFICENT!


----------



## CarlTN (Mar 19, 2014)

*Re: Deep Sky Astrophotography*



jrista said:


> Here is an image of Orion Nebula and Running Man. This is effectively an HDR image, as this region has EXTREMELY high dynamic range. I used 30x120s + 20x60s + 20x30s exposures to capture the ultra bright core detail where the Trapezium open cluster is, (30s and 60s exposures) as well as the dimmer outer regions of the nebula (120s exposures). I'd have liked to get 240s exposures, but Orion had moved behind my trees before I was able to do that. I wasn't even able to capture all of the dimmer dust detail...and for the detail I did capture, there is probably about 20 stops of DR. I'd probably need about 24 stops of DR to capture it all, meaning I'd need several more sequeces at 240s and maybe 480s to really pull out the dark dusty detail (which fills the entire region):
> 
> 
> 
> ...



You did very well on Orion, the other two are less compelling...especially the bottom one. Scaled too large, or otherwise too soft. I'll post the one I got of Orion with just my 135 f/2 in a few days. It doesn't compare of course, haha.

Well, 5 minutes at ISO 400 on a stationary star, seems like it would still blow it out. You're wide open at f/4, correct? (Maybe you're closed down for some of the esposures in the series, and open for others?) The Pleiades primary stars would be so blown that they would appear twice as large as they do, so I'm not sure how you're doing that. It seems like the way to do it, would be to expose for only a few seconds at ISO 100 for the brighter stars...then combine that with longer exposures at ISO 400 for the Nebulae and the fainter stars.


----------



## jrista (Mar 19, 2014)

*Re: Deep Sky Astrophotography*

Well, first, they aren't separate images. They are just crops of the same image. 

The scaling isn't the same kind of problem in astro as it is in regular photography. The general rule of thumb in astrophotography is that you SHOULD be OVERsampling. You don't want your stars to be pixel size...you want them to be several times pixel size. The rest of the softness is due to a number of things...tracking error, polar misalignment (in my case, at the time, it was about 2' misaligned, or 1/30th of a degree, so not all that bad, really), seeing. Seeing refers to atmospheric turbulence that causes stars to wobble and jump around.

So, the image is exposed and scaled properly...exactly as it should be, really. With a longer focal length, I'll only be oversampling that much more, but that's a good thing. The more pixels I can pack into any given object, the better. 

I was at f/4 ISO 400 for this series, although my exposure times differed. I took three separate sets of exposures, because the dynamic range in Orion Nebula is massive. The 30 and 60 second exposure sets were used to dim the core, which was indeed overexposed in the 120 second exposures. Additionally, mixing and matching ISO settings makes removing noise very difficult. Read noise levels increase as ISO drops, fixed patterns change, etc. meaning you need to use different sets of dark frames. However the semi-random and random noise contributions are also different, and when stacking images from different ISO settings, you usually end up with the worst common denominator in noise...thus noise is usually higher.

The best approach is to use a single ISO setting, at the same aperture, and only vary shutter speed. That minimizes the variables, and allows the intelligent aspects of stacking software (such as dynamic dark scaling) to work it's magic and give you the best results.


----------



## jrista (Mar 19, 2014)

*Re: Deep Sky Astrophotography*



Rienzphotoz said:


> Truly MAGNIFICENT!



Thanks! 



Jack Douglas said:


> Not sure I should even open my mouth here as I'm new to this and indeed very uneducated in the subject. I have modified my iOptron skytracker to add rigidity to the base and allow my gimbal head to be mounted on a horizonatal plane. I removed the gimbal swing arm and mounted my 300 X1.4 and was able to get quite good shots with pretty accurate focus. Aligning Polaris was not too much of an issue but it did need tweaking. With the now horizontal orientation of the iOptron base the gimbal worked really well in allowing smooth balanced movement of the lens.
> 
> However, last week I tried 300 X2 and found getting focus to be tricky becasue of lens movement due to lack of rigidity. I will try again and then perhaps have to accept that it's impractical. I'm not fully convinced, but obviously what I'm trying to do is not what anyone who is serious about the stars would be willing to accept.
> 
> ...



It looks like you want MUCH longer exposures. I'd say four times as long, 120 seconds, if you can manage it. I would start at 300mm, and not use the 1.4x TC. The longer the focal length, the more demanding the whole system is going to be on stability. You can do quite a bit of amazing work at 300mm...that would be wide field, so you could, for example, image the entire heart nebula in Cassiopeia, or get a wide field image of Rosette. That big lens is going to be your biggest drawback with the SkyTracker...you will need to get it as balanced as you possibly can, and make sure your polar alignment is as dead on as you can get it. Also, make sure you are imaging wide open, or close to it. You want f/2.8, although that might result in funky star halos, f/3.2 and f/3.5 are probably going to be your best friends.


----------



## jrista (Mar 19, 2014)

*Re: Deep Sky Astrophotography*

Here is Rosette nebula, in the constellation Monoceros (Unicorn), just to the east of Orion. Integration of 30x210s ISO 800 light frames, 30x darks, 30x flats, and 100x bias. Total exposure time 1h 45m. 







I wanted at least twice the light frames, and it seems I could probably do much better with 60x480s ISO 400, rather than ISO 800. Next time I get the chance, which may be tonight, I'm going to give it another go, and see if I can get more dim nebulosity in the periphery.


----------



## Jack Douglas (Mar 19, 2014)

*Re: Deep Sky Astrophotography*

Thanks Jrista!,

I'll get much more serious once the timer release arrives, hopefully in about a week. The moon has been too bright too. I have the stacking software downloaded but haven't tried it and don't know the process at the moment. Yes, once the gimbal is perfectly balanced it doesn't impact the tracker very much since it is so smooth - that'll be a positive. Of course I'll go beyond 30 sec as soon as I can do it with the timer.

The big problem for me is going to be knowing where to aim. Any good references on that??

For anyone that has purchased the iOptron skytracker, that wobbly base is an obvious design flaw. The external ring and 3 lock screws I added is just night and day better. I posted the picture on the other star thread.

Jack


----------



## expatinasia (Mar 20, 2014)

*Re: Deep Sky Astrophotography*



jrista said:


> Here is Rosette nebula, in the constellation Monoceros (Unicorn), just to the east of Orion. Integration of 30x210s ISO 800 light frames, 30x darks, 30x flats, and 100x bias. Total exposure time 1h 45m.
> 
> 
> 
> ...



Amazing pic, jrista. How do you even know where to look? I had always thought you would need a telescope (and a big one) to take such images. Amazing.


----------



## jprusa (Mar 20, 2014)

*Re: Deep Sky Astrophotography*



jrista said:


> Here is Rosette nebula, in the constellation Monoceros (Unicorn), just to the east of Orion. Integration of 30x210s ISO 800 light frames, 30x darks, 30x flats, and 100x bias. Total exposure time 1h 45m.
> 
> 
> 
> ...


Amazing, Thanks for sharing.


----------



## AmbientLight (Mar 20, 2014)

*Re: Deep Sky Astrophotography*



jrista said:


> Here is Rosette nebula, in the constellation Monoceros (Unicorn), just to the east of Orion. Integration of 30x210s ISO 800 light frames, 30x darks, 30x flats, and 100x bias. Total exposure time 1h 45m.
> 
> 
> 
> ...



Fantastic work JRISTA and many thanks for all the information you've provided! I didn't expect such results were possible. This is great stuff.


----------



## Northstar (Mar 20, 2014)

*Re: Deep Sky Astrophotography*



jrista said:


> Here is Rosette nebula, in the constellation Monoceros (Unicorn), just to the east of Orion. Integration of 30x210s ISO 800 light frames, 30x darks, 30x flats, and 100x bias. Total exposure time 1h 45m.
> 
> 
> 
> ...



Jrista...simply outstanding! 

After reading through your posts I have to say that I'm impressed by your knowledge, and thankful for the time you've taken to "write a short book" on the subject in this thread! ;D


----------



## Rienzphotoz (Mar 20, 2014)

*Re: Deep Sky Astrophotography*



jrista said:


> Here is Rosette nebula, in the constellation Monoceros (Unicorn), just to the east of Orion. Integration of 30x210s ISO 800 light frames, 30x darks, 30x flats, and 100x bias. Total exposure time 1h 45m.
> 
> 
> 
> ...


Jon, that is magnificent! Have you considered posting some tutorials on astro photography? I would love to learn how you make those images, they are just stellar.


----------



## Jack Douglas (Mar 20, 2014)

*Re: Deep Sky Astrophotography*

Poor Jon won't have any time for photography if he keeps writing all these wonderful explanations for all of us. Maybe a suggestion on a great book for beginners - Jon - or anyone else.

Seems more than just me is wondering how to know where to aim. I suspect this is not as easy as it might seem.

Jack


----------



## jrista (Mar 21, 2014)

*Re: Deep Sky Astrophotography*



Jack Douglas said:


> Thanks Jrista!,
> 
> I'll get much more serious once the timer release arrives, hopefully in about a week. The moon has been too bright too. I have the stacking software downloaded but haven't tried it and don't know the process at the moment. Yes, once the gimbal is perfectly balanced it doesn't impact the tracker very much since it is so smooth - that'll be a positive. Of course I'll go beyond 30 sec as soon as I can do it with the timer.
> 
> ...



Oh yes, the actual stand upon with the mount sits is probably one of the most critical factors, and is usually the limiting factor in terms of maximum capacity of the mount. A lot of midrange mounts ($1000-$3000) have capacities that top out at around 40-50lb, however that is usually because that's all the tripod or pier can handle before it begins to buckle. The mounts are often capable of handling a little more capacity than that if you place them on a sturdier tripod or pier.

As for knowing where to look, that's where an equatorial tracking GOTO mount is particularly handy. The GOTO mounts can be told to "go to" a set of RA/Dec coordinates, and they will. You have to have very good alignment for that to work...you need to have pretty precise polar alignment, and you need to align the goto feature itself by modeling the proper coordinates for known stars. Once you are polar aligned and have properly modeled, then you can use planetarium software (I use Microsoft WorldWide Telescope) to control the mount via ASCOM, and you can point at pretty much anything in the sky.

These days, I am now using plate solving. With either AstroTortilla+BackyardEOS, or Sequence Generator Pro, I plate solve, which takes a picture with my setup, and runs it through Astrometry.NET, which models the stars and DSOs in the image, figures out where you are actually pointing, then "syncs" the mount with a corrected model. It sometimes takes a few iterations of plate solving to fully correct the modeling of the mount, but once it does, pointing accuracy can often be within 50 pixels! (By default, pointing accuracy may be off by as many as a few tens of arcminutes on most mounts...accurate modeling is really what gives you good pointing accuracy, and that is usually only available on high end, $10,000+ mounts. I purchased Orion Atlas because it has EQMOD compatibility, which makes plate solving a very reliable option with SGP or AstroTortilla.) 

I don't know if the SkyTracker has any computer control capabilities. If not, I'd check to see if it has any kind of control capabilities with a hand controller, as that may allow you to do some basic modelling for basic GOTO functionality. If you don't have those (and I suspect not, most of the ultra wide field mounts don't offer that, as most people are going to be using 14mm to 50mm lenses, in which case all you need to do is point it in generally the right direction), then your just going to have to learn the sky, and learn how to do iterative refinement. It doesn't take long, once you start spending time outside under the sky, to learn the positions of the key constellations and what the stars in them look like in a photo. Once you get that far, you eventually learn how to recognize when certain important stars for constellations are in the frame. From there, you can "star hop"...change where the mount is pointing little by little and "hop" from known star to known star until your in proximity to what you want to image, then you can basically do a spiral search, taking an image, moving, taking and image, moving until your framed the way you want to be.

I think your case is a little more unusual, as your using a 300mm lens on a SkyTracker. Generally those mounts are used for much wider field work...I'd say at most 100mm, and generally probably closer to 24mm to 50mm. At 300mm your probably at the limits of what that little mount is capable of. If you ever want to stick the 1.4x or 2x TCs on your lens, then I would highly recommend you bump up to the next level...like the Orion Sirius. That's a full blown Equatorial GOTO mount, and you could then (with an EQDIR cable, bought separately) have complete computer control over the mount...and you could plate solve, use planetarium software for pointing, and do full blown imaging like I am doing with BackyardEOS, Sequence Generator Pro, Nebulosity, etc.


----------



## jrista (Mar 21, 2014)

*Re: Deep Sky Astrophotography*



expatinasia said:


> Amazing pic, jrista. How do you even know where to look? I had always thought you would need a telescope (and a big one) to take such images. Amazing.



Thanks! 

As far as finding things, I use Microsoft WorldWide Telescope (WWT) to point my mount. Before I do that, I "model" my skies with a plate solving tool, which can figure out the stars and deep sky objects in a photo by referencing indexes and doing spatial mapping and modeling. The plate solvers "sync" their model to the mount, after which I am able to point very accurately, usually within an arcminute or two, sometimes within arcseconds. So, all I really have to do is use WWT to find what I want to image, highlight it, and tell it to "slew" the mount. That's all there really is to it!


----------



## jrista (Mar 21, 2014)

*Re: Deep Sky Astrophotography*



AmbientLight said:


> Fantastic work JRISTA and many thanks for all the information you've provided! I didn't expect such results were possible. This is great stuff.



Thanks! And your welcome.  It's possible to do MUCH better than I have. I'm still a relative novice. Even with just a basic telescope and a DSLR, there are people out there who are more skilled and have gotten far more beautiful images than I have. I was actually surprised that the Canon 7D did as well as it did on Rosette...lot of hydrogen alpha (Ha) emission there, however most DSLRs, including the 7D, only pass about 15-20% of Ha wavelengths (it's only a 3nm bandpass). The fact that I was able to extract as much red nebula detail as this is pretty lucky.


----------



## CarlTN (Mar 21, 2014)

*Re: Deep Sky Astrophotography*



jrista said:


> Well, first, they aren't separate images. They are just crops of the same image.
> 
> The scaling isn't the same kind of problem in astro as it is in regular photography. The general rule of thumb in astrophotography is that you SHOULD be OVERsampling. You don't want your stars to be pixel size...you want them to be several times pixel size. The rest of the softness is due to a number of things...tracking error, polar misalignment (in my case, at the time, it was about 2' misaligned, or 1/30th of a degree, so not all that bad, really), seeing. Seeing refers to atmospheric turbulence that causes stars to wobble and jump around.
> 
> ...



Thanks, I’m familiar with “seeing”. The unwanted, different noise at different ISO’s in your stacking makes sense. Like I said, I was just trying to make sense of why the bright stars aren’t more blown out than they are, in your final image. Obviously I don’t know much of anything about the technique. Can you explain “dynamic dark scaling”? You don’t have to use over 300 words, I don’t want to take up all your shooting time!


----------



## jrista (Mar 21, 2014)

*Re: Deep Sky Astrophotography*



Northstar said:


> Jrista...simply outstanding!
> 
> After reading through your posts I have to say that I'm impressed by your knowledge, and thankful for the time you've taken to "write a short book" on the subject in this thread! ;D





Rienzphotoz said:


> Jon, that is magnificent! Have you considered posting some tutorials on astro photography? I would love to learn how you make those images, they are just stellar.



Thanks, guys! For all your kind words.  

I'm happy to write some tutorials. I have an area set up on my blog at jonrista.com for that. I'd love to see more people get into astrophotography. I've been limited myself to just the moon and larger solar system objects, and maybe some of the larger nebula like Orion, until I got myself a good tracking mount. It's a complex form of photography, but if you like a challenge and like all the gadgetry and math and tinkering and experimenting that goes into astrophotography, you'll love it!

I'd like to get a little bit more experience under my belt before I do write any tutorials...some things I'm still learning and refining my knowledge of. Learning more about the software options, for one. There are a LOT of processing techniques I still need to learn, and some additional tools (like PixInsight). One of the biggest issues, one of the most difficult to deal with unless you get a $20,000 mount, is tracking performance. I'm somewhat "lucky" to be imaging at "only" 600mm...most telescopes are around 1600mm and longer, some of the larger ones are well over 3000mm, and with a barlow, you can get as long as 9000mm or longer! 

There is inherent error in all tracking, due to imperfections or precision limits in gears and worms and the like. It's called Periodic Error. There are also sources of non-periodic error, such as seeing (atmospheric turbulence), flexure (the mechanical flexing of anything on the mount, including the tripod, the mount itself, the telescope and guidescope, etc.), wind, etc. A real high end mount, like the 10Micron GM2000HPS, which uses "absolute" encoders which track the absolute position of both the RA and Dec axes with extremely high precision, is basically immune to most of these sources of error. Periodic error, unexpected movement due to wind, even seeing effects, are delt with by the absolute encoding and built-in sky modeling in a mount like the 2000HPS. That sucker generally costs about $24,000 for a complete package, though. 

Tracking issues on lower end mounts are usually delt with by "guiding". Guiding uses a secondary scope, usually smaller than the primary scope, along with a small video camera and special guiding software, to lock onto a specific star, model it's shape, identify the "centroid" (an identifiable center point that can be reliably found and regularly tracked), and send correcting guide signals to the mount to tell it to slow down or speed up relative to "sidereal rate". This can solve tracking errors that are primarily due to periodic error. If you use "Off-axis Guiding", you can also solve tracking error that might be caused by various sources of flexure (which pretty much every scope is going to have to one degree or another), slight movement due to wind, etc. 

Tracking is probably one of the toughest things to learn about astrophotography, but also one of the things you have to tackle early on to get images like the Rosette image I last shared. You have to get tracking error, in terms of arcseconds, to an average level below your image scale (the relative size of a pixel in arc seconds)...for example, the 7D has 4.3µm pixels, and with a 600mm lens, my image scale is 1.48" (arcseconds)...so for ideal tracking, my RMS error needs to be ~0.7", about half the image scale. I have been able to get my tracking accuracy down to 1" to 1.2", but I haven't yet figured out how to consistently get it below that. 

Once I do, I'll be more able to image things on a consistent basis, and I'll have more data to stack and learn processing techniques with. I hope to be there by summer, at which time I'll probably start writing tutorials on my site.


----------



## jrista (Mar 21, 2014)

*Re: Deep Sky Astrophotography*



Jack Douglas said:


> Poor Jon won't have any time for photography if he keeps writing all these wonderful explanations for all of us. Maybe a suggestion on a great book for beginners - Jon - or anyone else.



Hah! I truly wish that was my problem!  My biggest problem, really the curse of astrophotographers everywhere, is clouds! I always have cloud cover. For example, tonight...clouds. Hence the reason I'm wasting my time here answering all your fine questions. 



Jack Douglas said:


> Seems more than just me is wondering how to know where to aim. I suspect this is not as easy as it might seem.



It is definitely a technical artform. I knew a lot about photography and the technology behind it, but once I started getting more into AP last year, since then I've learned a TON more, or at least my knowledge of things has become more refined. Everything has to be more precise and accurate in astrophotography. Everything is exaggerated. Everything needs more, more, MORE, MOAR!!!!! AAARRR!!!

It really just takes practice, though, like anything else. You don't necessarily need to understand all the technical and mathematical underpinnings. That knowledge helps, especially when you have to dig in and start dealing with the technical aspects of mounts and tracking error and guiding performance that make your round stars go eggy. The wider your field, though, the easier it is. Your kind of at a middle ground with 300mm...you have some challenges ahead of you, but given your maximum aperture of f/2.8, and the moderate focal length, you have some SIGNIFICANT advantages working for you as well. I think, once you get some good tracking beyond 30 seconds, and learn how to create a fully calibrated integration of your images, you'll be surprised at what you can do.

Only real word of advice I can give you now, is, get as many subs (individual light sub frames) as you can. Noise is the biggest single issue in astrophotography. It's why people will spend two, three, five nights imaging the exact same object over a period of weeks or months to get 50, 70, 100 images of the exact same thing...so they can reduce noise. Remember that dynamic range in a properly calibrated stack of images is FAR greater than that of any normal single photograph, and probably greater than that of most HDR photographs. Were talking 20+ stops if you integrate enough frames to reduce noise to the point of near-invisibility. 

Star centroids consume the vast majority of that dynamic range....out of that 20-24 stops of dynamic range, all the nebula detail lives in the bottom few stops, and the vast bulk of post processing work is geared towards lifting it all out of the deep shadows and making it visible. All of the images I've posted so far looked entirely black with a salting of bright stars...I had to DIG and pull out the nebula detail out of the wicked depths...that's pretty much what astrophotography is...digging the faintest little bits of detail out of the lowest couple of bits of data in your final integrations.

I hang out on a couple of astro forums on the net. I've seen a lot of beginners posting their first images, and you can see little shreds of nebula here and there due to too few subs, lots of blown out stars, lots of egg-shaped stars due to bad polar alignment and poor tracking. If you want to start out the gate getting acceptable results, then the single best piece of advice you should follow, beyond tracking performance itself, is to maximize the quality of each and every sub. Don't stop at 20, or 30. If you have the option, point your setup at one place in the sky, at most two hours after it rises in the east, and let your system track it all night long, and take images all night long, until it starts to set in the west. Find the broadest horizon you can with the best, and darkest, view of the sky that you can. Track...and EXPOSE. That's the real trick. That's what most of the novices miss (and the one reason why I've been able to get decent results despite only having owned my equipment for less than a month.) You need to get the longest subs possible (without clipping stars, or at least without clipping them too much...exposure equals greater signal strength), and you need to get as many of them as you possibly can (total number of subs equals higher SNR, which means lower noise in the final integration). THAT will get you some awesome results, especially with your f/2.8 aperture.


----------



## jrista (Mar 21, 2014)

*Re: Deep Sky Astrophotography*



CarlTN said:


> Thanks, I’m familiar with “seeing”. The unwanted, different noise at different ISO’s in your stacking makes sense. Like I said, I was just trying to make sense of why the bright stars aren’t more blown out than they are, in your final image.



Well, as far as stars go....they are, stars.  When it comes to the cutting edge of "low light" imaging, most of the more recent technological innovations that you can find over on sites like ImageSensorsWorld, are rated on their ability to see "in starlight". Starlight is in the "Fraction of a Lux" range as far as total illumination goes...they are exceptionally dim, and pretty much anything, including a half moon, can blot them out of existence.

At ISO 400, under 0.01 Lux, your sensor "speed" is actually quite slow...relatively speaking. In normal photography terms, ISO 400 is moderately fast. ISO 1600 is quite fast. ISO 6400 is ultra fast. In imaging, ISO 400 is probably more akin to "normal" ISO 50, and ISO 1600 is more like ISO 200 or 400. You actually have a lot of time to expose before your pixels saturate, even with a sensor like the 7D's, which only has ~20ke- at max saturation @ ISO 100 (and only around 6ke- at ISO 400!). 

It should be noted that the very central part of most stars, the "centroid", is often clipped. When I image galaxies, which I usually do at ISO 800 because they are so dim, most of the larger and brighter stars are a little clipped in the center. But that usually isn't a big deal, because of the way you process. Processing is all about bringing up the shadows without modifying the highlights at all...your compressing a MASSIVE amount of dynamic range into 8 stops...so its lift, lift, lift, lift! In astrophotography terms, it's called stretching, but that is only because we usually start out with 32-bit floating point TIFF images, which are capable of storing dozens of stops of dynamic range...so we "stretch" our images initially, then convert down to 16 bit integer TIFF, then do some more stretching, pushing, and pulling with levels and curves to bring out the nebula detail. 



CarlTN said:


> Obviously I don’t know much of anything about the technique. Can you explain “dynamic dark scaling”? You don’t have to use over 300 words, I don’t want to take up all your shooting time!



Dark frames are intended to remove fixed pattern and dark current noise from light frames. In order for that to be possible, the dark frames must be created at the same shutter speed, ISO setting AND temperature as the light frames...since all three of those factors affect how dark current (which doubles/halves every 6°C) and fixed pattern noise present. Dynamic dark scaling is a newer technique in applying dark frames, that allows you to use darks taken within an acceptable relative temperature range to your lights. There are a few different specific algorithms, but the general idea is to scale up or down the noise levels in a master dark to match the temperature of each light frame as the dark is subtracted from them one by one. 

It goes without saying that it's extremely difficult to create a library of dark frames that matches every potential light frame. You have a number of standard exposure times...30s, 60s, 90s, 120s, 180s, 210s, 240s, 300s, 360s, 420s, 480s, 540s, 600s. On Canon sensors, the two most acceptable ISO settings are usually 400 and 800...go below that, and read noise is too high, go above that and read noise doesn't shrink appreciably relative to the drop in max saturation. Some people use ISO 1600 anyway, and sometimes it's just plain necessary. That right there is a factorial of 13 shutter speeds and three ISO speeds. Throw in the range of temperatures from -10°C to 80°C, with a tolerance of 2°C, and you have a factor of 13 shutter speeds, three ISO speeds, and 45 distinct temperatures. It's practically impossible to create a dark frame library complete enough that you could match the right darks to any given light frame. 

Hence the benefit of dynamic dark scaling. It'll let you create a library of darks spanning far fewer specific temperature levels. You might stick the camera in the freezer for -10°C and 0°C, in the refrigerator for 10°C, and maybe get some darks for 20°C and 40°C. Dynamic dark scaling can take care of the rest. Bitch of it is, you still need to get darks for these five temperatures for the same 13 shutter speeds and three ISO settings, but a least it's only five temperatures, rather than 45 temperatures!


----------



## CarlTN (Mar 21, 2014)

*Re: Deep Sky Astrophotography*



jrista said:


> CarlTN said:
> 
> 
> > Thanks, I’m familiar with “seeing”. The unwanted, different noise at different ISO’s in your stacking makes sense. Like I said, I was just trying to make sense of why the bright stars aren’t more blown out than they are, in your final image.
> ...



Ok, never knew you were sticking the camera in a freezer. Is that on location at your lens and mount? Or do you rely on the cold ambient temperature, and somehow measure the camera's sensor temperature? I don't know how you'd do that. And isn't it freezing the battery, robbing it of charge? Or are you using some type of AC or regulated power supply for the camera?


----------



## jrista (Mar 21, 2014)

*Re: Deep Sky Astrophotography*



CarlTN said:


> Ok, never knew you were sticking the camera in a freezer. Is that on location at your lens and mount? Or do you rely on the cold ambient temperature, and somehow measure the camera's sensor temperature? I don't know how you'd do that.



All modern DSLRs have temperature sensors built in. It's how cameras know how to turn themselves off, or turn off live view, when they get too hot. The temperature is stored in EXIF metadata for each image, and the tool I'm using to build my dark library, BackyardEOS, sticks the temperature in the automaically generated filenames. So it's pretty easy to build a dark frame library that way. 

The standard approach for taking darks is to take them right after your done taking your lights, on site. The idea there is that by doing it after the lights, on site, you create them at the same temperature. Problem with that approach is that temperature fluctuates, even when your taking your lights, and sometimes by a lot. I've had 8-12° swings during my light frame imaging, peak to peak. Once you start taking your darks, the same thing is likely to happen. So getting temperature-matched darks is very difficult. Since dark current changes by a factor of two every six degrees, a swing of 8-12 degrees in your lights makes it pretty difficult to match up darks. It's possible, but it usually involves dividing up your images into batches of equal temperature for calibration, which also need the darks to be divided up. You need at least 30 darks, preferably 50, to get good results, and it's pretty difficult to get that many darks of a single temperature.



CarlTN said:


> And isn't it freezing the battery, robbing it of charge? Or are you using some type of AC or regulated power supply for the camera?



I use an AC adapter for my camera when I'm imaging. Imaging the night sky takes hours...I've had my equipment outside, tracking, and imaging for six to seven hours strait. Using batteries is impractical. As for temperature, my camera, my entire setup actually, has endured much greater cold than I think my freezer is even capable of achieving. When I first started in early February, there were a couple nights where the temperature at night got down to almost -24°F in the early hours before dawn, which is around -30°C. Even during the last week of February, we had a couple of nights where the temps were around -20°C. 

I know a couple of places out under true dark skies, out on the plains east of the Rockies, where it is very flat and wide open (great horizon view, excellent for imaging). I haven't taken my gear out there yet, as I need a powerful remote power supply (I'm thinking of getting an ultra-quiet 55dB 2000W portable generator), but out there, during January and February, the temperatures can get even colder...and with wind chill, any residual heat that builds up because of the electronics will be constantly sucked out...so were not just talking cold, were talking deep freeze with active cooling! I was actually out there a couple years ago during our last Total Lunar Eclipse (I think that was Dec. 2010), and it was one of the coldest experiences of my life. 

So freezing my camera in my freezer is actually rather mild. ;P


----------



## CarlTN (Mar 21, 2014)

*Re: Deep Sky Astrophotography*



jrista said:


> CarlTN said:
> 
> 
> > Ok, never knew you were sticking the camera in a freezer. Is that on location at your lens and mount? Or do you rely on the cold ambient temperature, and somehow measure the camera's sensor temperature? I don't know how you'd do that.
> ...



How much cold can the shutter take? I had thought that temperature ratings for cameras, were meant to be a guideline for overall functionality, and not just the battery. I was out when it was "only" -3F here with my 6D at the end of January, taking wide shots over my oak tree. I was only out about 25 minutes though...the battery held up fine, didn't even have a full charge. I, however, was fairly cold...at least my hand was whenever I took it out of the glove! I wore wool insulated boots, there was about 3 inches of snow, frozen over. I can't imagine being in -30F ambient, with wind on top of that. At that point, I would rather just look at other people's photographs! (Especially if I'm not only not getting paid for the shoot, but not getting paid AHEAD OF TIME for the shoot...haha). Heck, even with the amount of knowledge and money it took for your setup...I'm content to just look at yours...and occasionally share my "all in one exposure" wider shots.


----------



## jrista (Mar 21, 2014)

*Re: Deep Sky Astrophotography*

Once you get below around -12°F to -15°F, the mechanical and some electronic things definitely start having some trouble. I remember when I was imaging the moon all those years ago that the shutter sounded as though it was struggling. Shutter speeds are pretty slow, though, you usually have second long to many minute long exposures with solar system and deep sky imaging. With slower shutter speeds, shutter performance isn't nearly as important as in high speed photography.

Long term, I don't plan on staying with a DSLR for my astro work. I'm probably going to be moving to an SBIG STx-8300M, not sure whether it will be the STT or STF line. It may be another brand, QHY makes some great imagers, Atik makes some good ones that are usually cheaper than the competition (i.e. it usually costs about $10k for a true 36x24mm FF CCD sensor imager, Atik sells one for about $6000). Astro CCD imagers are specifically built for operation in the extreme cold. Most have a dual-stage TE cooler, and the temp deltas range from -40 to -80 degrees Celsius from ambient. During winter you usually leave the cooler off, or turn it on low. During summer you crank it up. The general idea is to keep the sensor temperature to somewhere between -10° to -20°C.

Dedicated astro imagers also support all the astro imaging stuff. They are monochrome, so generally have higher spatial resolution than DSLRs while still having larger, more sensitive pixels. They often directly support, or even have built in, off-axis guiding (OAG) sensors. They support filter wheels, so you can pop in LRGB and Ha, SII, and OIII and opaque filters, allowing you to program and completely automate extensive multi-spectral imaging sessions. 

For a complete astro CCD package from SBIG, for example, with the imager, the filter wheel, OAG, and filters, it usually costs about $5000. So I'll be sticking with my DSLR for at least the next year. ;P


----------



## CarlTN (Mar 21, 2014)

*Re: Deep Sky Astrophotography*



jrista said:


> Once you get below around -12°F to -15°F, the mechanical and some electronic things definitely start having some trouble. I remember when I was imaging the moon all those years ago that the shutter sounded as though it was struggling. Shutter speeds are pretty slow, though, you usually have second long to many minute long exposures with solar system and deep sky imaging. With slower shutter speeds, shutter performance isn't nearly as important as in high speed photography.
> 
> Long term, I don't plan on staying with a DSLR for my astro work. I'm probably going to be moving to an SBIG STx-8300M, not sure whether it will be the STT or STF line. It may be another brand, QHY makes some great imagers, Atik makes some good ones that are usually cheaper than the competition (i.e. it usually costs about $10k for a true 36x24mm FF CCD sensor imager, Atik sells one for about $6000). Astro CCD imagers are specifically built for operation in the extreme cold. Most have a dual-stage TE cooler, and the temp deltas range from -40 to -80 degrees Celsius from ambient. During winter you usually leave the cooler off, or turn it on low. During summer you crank it up. The general idea is to keep the sensor temperature to somewhere between -10° to -20°C.
> 
> ...



I don't blame you at all, there. Ever see any unusual objects when you're out? I find that I get at least one satellite most times I do night imaging. (I realize in a narrower FOV such as at 600mm on a crop sensor, you won't get as many, obviously). One I did about a week ago, with the 135 f/2 on my 6D, pointed north with the horizon in the bottom...only a 30 second exposure...captured two satellites, and I forget how many jets (it was a Friday night, usually loads of air traffic on Fridays). I could only see one or two of the jets with the naked eye. I know you're fond of capturing meteor showers...but just wondered if you've seen anything more strange than that?

I wish I could have captured some of the bright meteors, but there's no forewarning. The one that I heard its sonic boom last year, would have been nice to attempt to capture. But you can never know about those big ones I guess.

I would think there are other interesting military or otherworldly sky phenomena you could see out in the desert southwest...that's probably not something the heavily invested astro imaging people you converse with on those forums, will discuss often though...lest they be mocked or something! Oh wait, nobody ever mocks anyone on forums, do they?


----------



## Rienzphotoz (Mar 21, 2014)

*Re: Deep Sky Astrophotography*



jrista said:


> Northstar said:
> 
> 
> > Jrista...simply outstanding!
> ...


You are most welcome, your work deserves all the praise that it gets. I am no professional photographer but I do conduct lots of free workshops for many colleagues my office and also at my kids school ... although I am not an expert, I feel I learn more as I teach, the little that I know, to others. I think many CR members would agree that if you did start tutorials (as and when you get time) from whatever that you know now (which I think it is a lot), on Astrophotography, there will be lots people who will learn/benefit from those tutorials. FYI, I did read the "Extreme Digital Upscaling" page on your website and loved it, must confess that I'll have to revisit that page a few times to absorb ... so having seen your writing/explaining style, I think your tutorials would be a great benefit to many like me.


----------



## Jack Douglas (Mar 21, 2014)

*Re: Deep Sky Astrophotography*

Jon,

Thanks ever so much. I now know enough to start seriously learning.

Jack


----------



## jrista (Mar 21, 2014)

*Re: Deep Sky Astrophotography*



Rienzphotoz said:


> jrista said:
> 
> 
> > Northstar said:
> ...



Thanks, Rienz, I really appreciate that. I have a bit of a backlog of articles I've wanted to write on my site for a while. I'll have to start working on them, especially now that I know there may be some people who are actually interested in reading.


----------



## TheJock (Mar 22, 2014)

*Re: Deep Sky Astrophotography*

I know there's a whole world of learning on this subject, but if I wanted to try my hand at those lovely circular star trails one evening here in Dubai, would the following be acceptable.

1. Go to Atlantis on the Palm as it's 7klm out to sea and should provide less City streetlight "noise"
2. Camera (manual mode facing towards the north star) on tripod set at 100ISO, f8, AWB, evaluative metering and bulb (using the 18mm end of the 18-55STM kit lens from my 70D)
3. fire shot for 3 minutes

Would this get me one of those nice shots??
Thanks for any input guys, I just fancy giving this a go.


----------



## jrista (Mar 22, 2014)

*Re: Deep Sky Astrophotography*

Jock,

Few things. First, going 7km off shore from Dubai probably won't do anything to improve your light pollution situation. You'll be over the ocean, which is going to reflect a good percentage of the light from Dubai, which is a pretty concentrated center of LP. You'll probably still be in a red zone, or maybe orange-red transition zone. You would probably need to head more like 50-100km out of town to get darker skies, regardless of whether it's into the desert or near the shore.

You should be using a manual camera mode (bulb will work), thus the metering mode is meaningless, since your choosing the exposure. You also probably want to shoot wide open, as stopping down will make stars flare, which will affect the quality of your star trails. 

You will also need to expose for FAR more than just 3 minutes in total. You will want to expose for as long as you can to start getting trails, however even over three minutes, stars are only going to start looking like very, very short little streaks. To get full arcs, you will need to take exposures for hours. To get semi-circular arcs, you will need to take exposures for the entire night. Also remember that you need to point towards a pole to get arcs. If you point near the celestial equator, you get strait streaks that start to bend more and more as to reach the corners of the frame. 

I would say set ISO to 100 or 200, f/5.6, AWB probably doesn't matter, bulb mode. You will want a shutter release that allows you to configure exposure length, delay, and count, so you can just set it up to take 100-300 shots that are anywhere from 30 seconds to several minutes each, and just let it rip all night long. After about an hour of exposures, you'll have enough frames to create very short star trails. After a few hours, you should have some recognizable arcs, and you should be able to tell fairly well where the pole (whichever pole your pointing at) is. After 6-8 hours, you should have very long, circular trails that clearly show the rotational shape and speed of the stars in the sky, and the location of the celestial pole should be very clear.


----------



## Rienzphotoz (Mar 23, 2014)

*Re: Deep Sky Astrophotography*



jrista said:


> Jock,
> 
> Few things. First, going 7km off shore from Dubai probably won't do anything to improve your light pollution situation. You'll be over the ocean, which is going to reflect a good percentage of the light from Dubai, which is a pretty concentrated center of LP. You'll probably still be in a red zone, or maybe orange-red transition zone. You would probably need to head more like 50-100km out of town to get darker skies, regardless of whether it's into the desert or near the shore.
> 
> ...


That is some very good advise Jon ... now I need to get my lazy ass to the desert one of these nights (before it gets hot as hell) and practice.


----------



## TheJock (Mar 24, 2014)

*Re: Deep Sky Astrophotography*



jrista said:


> Jock,
> 
> Few things. First, going 7km off shore from Dubai probably won't do anything to improve your light pollution situation. You'll be over the ocean, which is going to reflect a good percentage of the light from Dubai, which is a pretty concentrated center of LP. You'll probably still be in a red zone, or maybe orange-red transition zone. You would probably need to head more like 50-100km out of town to get darker skies, regardless of whether it's into the desert or near the shore.
> 
> ...


This is great advice, thank you for taking the time to reply in such detail, I now have a firm basis on which to explore!! I'll need to find a dark bit of desert too by the sounds of it!! 8)


----------



## jrista (Apr 3, 2014)

*Re: Deep Sky Astrophotography*

I reworked my Rosette Nebula image with a new software package called PixInsight. A VASTLY superior product for astrophotography, it gives me so much more control over everything, and allows me to tweak specific layers and scales of detail independently without messing with my color balance. This version of Rosette is much more color accurate than the nearly monochrome-red version that I posted before...and it has a bit more color contrast, so certain details should be easier to see than before:


----------



## CarlTN (Apr 3, 2014)

*Re: Deep Sky Astrophotography*



jrista said:


> I reworked my Rosette Nebula image with a new software package called PixInsight. A VASTLY superior product for astrophotography, it gives me so much more control over everything, and allows me to tweak specific layers and scales of detail independently without messing with my color balance. This version of Rosette is much more color accurate than the nearly monochrome-red version that I posted before...and it has a bit more color contrast, so certain details should be easier to see than before:



Interesting, and I do like the color detail of the nebula, but overall it just looks softer than I'd like. 

Btw, here are some interesting links, or at least they were interesting to me (not overly scientific of course).

http://www.nbcnews.com/science/space/far-out-icy-world-widens-our-solar-systems-frontier-n62286

http://www.ctio.noao.edu/noao/content/Dark-Energy-Camera-DECam


----------



## Northstar (Apr 3, 2014)

*Re: Deep Sky Astrophotography*



jrista said:


> I reworked my Rosette Nebula image with a new software package called PixInsight. A VASTLY superior product for astrophotography, it gives me so much more control over everything, and allows me to tweak specific layers and scales of detail independently without messing with my color balance. This version of Rosette is much more color accurate than the nearly monochrome-red version that I posted before...and it has a bit more color contrast, so certain details should be easier to see than before:



simply fantastic! it feels like i'm looking at it through an ultra powerful telescope.


----------



## jrista (Apr 3, 2014)

*Re: Deep Sky Astrophotography*



CarlTN said:


> Interesting, and I do like the color detail of the nebula, but overall it just looks softer than I'd like.



It's a nebula...they generally tend to be "soft", what with being a bunch of whispy gas and all. ;P As for the stars, I purposely "decrispified" them and made them rounder/softer because otherwise they completely dominated the image, making it difficult to actually see the nebula. Part of the reason my stars end up too bright and crisp is the centroids are getting just a touch clipped during my exposures (necessary, to expose the nebula properly), and during processing the centroids get enlarged. So the star reduction routine is really just restoring the proper look to the stars anyway.



Northstar said:


> simply fantastic! it feels like i'm looking at it through an ultra powerful telescope.



Thanks! Rosette is actually a fairly large nebula. It's larger than the Orion Nebula, which you can sort of see with your naked eye, too large even to fully fit in my 600mm FoV. The entire region is probably a bit bigger than your thumb if you held it out about a foot and a half from your face over the sky...just to give you an idea of how large this region of space actually is.  Sadly, Rosette is so dim that unless you had a really garganguan telescope with multi-foot sized aperture, you probably could never observe it visually.


----------



## CarlTN (Apr 4, 2014)

*Re: Deep Sky Astrophotography*



jrista said:


> CarlTN said:
> 
> 
> > Interesting, and I do like the color detail of the nebula, but overall it just looks softer than I'd like.
> ...



Actually the stars in this image appear soft...as does really the entire image. Just calling it like I see it.


----------



## jrista (Apr 4, 2014)

*Re: Deep Sky Astrophotography*



CarlTN said:


> jrista said:
> 
> 
> > CarlTN said:
> ...



Indeed, soft exactly as they are supposed to be.  No one wants HARD stars in their astrophotos...they are overbearing and dominating, and distract from the rest of the image, from the more interesting aspects of the image.


----------



## Rienzphotoz (Apr 4, 2014)

*Re: Deep Sky Astrophotography*

Hi Jon,
If I go with a budget of $1000 (along with my current gear below), what telescope and/or accessories would I need to start off Astrophotography?
Thanks


----------



## jrista (Apr 4, 2014)

*Re: Deep Sky Astrophotography*

Hi Reinz. When it comes to astrophotography, the mount is pretty much the most important thing. Most astrophotographers who have even moderately diverse goals (i.e. just galaxies and nebula) are going to need to use multiple telescopes with different focal lengths, or at least one telescope with barlows and focal reduces, to get a field of view wide enough or narrow enough to frame their subjects properly. A good mount can last you for many, many years, where as telescopes (or, for that matter, camera lenses) usually come and go until you hit the real high end (i.e. 20" RCOS or PlaneWave telescopes). 

For $1000, you can get yourself an entry-level mount. Something like the Orion Sirius, which is the little sibling of the Orion Atlas. The Sirius has a capacity of 30lb, which for visual is generally fine, but that pretty much equates to 15lb for astrography (the Sirius doesn't have the most sturdy tripod, so you REALLY have to stick to the 50% capacity limit for imaging work). That is practically nothing in terms of capacity, but if you just stick to your DSLR and lenses, it'll at least get you started. 

The Orion Atlas is a much more capable mount, it's capacity is 40lb, however imagers have been putting on 60-70% of the capacity and getting excellent results. Visual observers have put over 50lb on this mount when using sturdier tripods or full blown piers. The Orion Atlas is $1499, however it's fairly frequently on sale for $1399, and at times has been as low as $1200. Given how important the mount is, especially if you think you might want to move up from your lenses to a real telescope at some point in the future (and entry cost for telescopes can actually be pretty low...for example, the Astro-Tech AT6RC, a 6" Ritchey-Chretien telescope, is only $399 and it's designed specifically as an astrograph.) If you can muster it, I highly recommend getting the Orion Atlas mount, even though it's more than your $1000 budget. It will give you LOTS of room to grow in the future if you find that you like astrophotography (it could even be "the" mount you use for the next ten or twenty years....many people used the predecessor to the Atlas/EQ6 class mounts for about that long.) 

From your existing equipment, the 5DIII hands down. Don't use a Nikon for astrophotography...their nickname in our community is "Star Eaters", since they *clip *to the black point, rather than using a bias offset (one of the many ways Nikon "cheats" their way towards cleaner shadows .) Canon's use of a bias offset is the reason there is a lot of banding in their shadows, which isn't good for regular photography. However since in astrophotography we use bias frames to remove the bias from the signal, Canon DSLRs are actually a lot better...they preserve more stars and deep nebula detail. So definitely use the 5D III. 

You have a good range of lenses as well for "wide field" work. The 40/2.8 @ f/4 and 50/1.4 @ f/3.5 are both excellent for "whole constellation" images (for example, you could image the entirety of the core Orion constellation, as well as most of his club and kill: http://bit.ly/1lF7hSp) The 100mm Macro @ f/4 is a great lens for imaging entire small constellations, or for imaging parts of larger constellations (for example, it would neatly encompass the core of Orion, but not his club or kill: http://bit.ly/1jIciah) The 70-200 at 200mm @ f/4 is great for narrower regions, small constellations (for example, 200mm would encompass Orion's Belt and Sword, and the small reflection nebula M78: http://bit.ly/1mOwpGH) The 100-400 at 400mm @ f/8, while a bit slower and probably requiring more equipment (such as a guider, which itself would probably require a number of additional accessories to properly mount next to your camera), is good for imaging nebula themselves (for example, it would encompass just Orion's sword, which includes Orion Nebula (M42/M43) and Running Man Nebula: http://bit.ly/1ltmAeo; or it would encompass just Orion's Belt, which includes Horse Head and Flame Nebulas, IC434, and a number of small reflection nebula: http://bit.ly/1dSzPFJ).

If you go with just the mount, you will be able to attach your DSLR and a lens. The 100-400mm is probably not quite going to work, as you would need pretty steady tracking to image at f/8...that's pretty slow. Were talking 1" (" means arcsecond, ' means arcminute, 60 arc minutes per degree) tracking, which is not easy to achieve. So your probably going to be stuck at 200mm and less until you decide to upgrade. Thing is, that is really the best place to start anyway, as at those focal lengths, tracking error is really forgiving, so you should be able to track for several minutes, maybe as much as five minutes, without appreciable star elongation or trailing, allowing deep exposures of wide regions of the sky (which, during the two times of year when the milky way is up, are PACKED with IMMENSE swaths of nebula). 

Unguided imaging is basically the domain if the wide and ultra wide field. If you want to see the kinds of images you can get at those scales, you should check out AstroBin. Plenty of good examples there (better than anything I've done as of yet.) 

If you get an Orion Sirius mount, which is $1000, then that will suffice for DSLR with 200mm and less. You'll need to get a better mount than that if you want to do more. There are a lot of small APO refractors on the market, ranging in price from around $500 to as high as $10,000 or more, however most of the smaller, lighter ones that would work on a Sirius fall into the same general focal range that you already have with your Canon lenses (200mm to ~800mm). The logical upgrade for you would be to eventually move to a Cassegrain type OTA (Optical Telescope Assembly). Cassegrains include your standard SCT (Schmidt-Cassegrain Telescope), the Celestron EdgeHD (an Aplantic SCT, designed specifically to support a wide and flat field, right into the corners, for imaging), and the Ritchey-Chretien cassegrains (primarily those from Astro-Tech.) Meade also makes some Aplantic SCTs like Celestrons, however they tend to be more expensive, despite not really offering anything more, and there is one special benefit to the Celestron EdgeHD OTAs: They support Hyperstar, a special conversion mod that allows you to do ultra wide field imaging (~200-400mm) at f/2 (REALLY FAST...you could get really deeply exposed images in a couple minutes at that aperture.) 

Generally speaking, the best upgrade from DSLR+Camera Lens imaging is to move to something like the Celestron EdgeHD 8" SCT, or the Astro-Tech AT8RC 8" Ritchey-Chretein. Both are reasonably priced, although Astro-Tech's prices are really hard to beat for the quality, optical design, and overall capabilities for imaging. For either of these, you would really want at leas the Orion Atlas (or the equivalent from Celestron, the CGEM or CGEM DX, however the Atlas is really the better option due to the rich community, EQMOD, and the option for installing belt mods to improve tracking and guiding accuracy down the road.)

My recommendation is pick up the Orion Atlas EQ-G, and use your 5D III and 50mm, 100mm, and 70-200mm lenses. You should be able to just bolt your camera to the included Vixen dovetail that comes with the mount, and not bother with purchasing any additional accessories initially. You will need to learn how to polar align the mount (the Atlas comes with a built-in polar finder scope, which once properly centered (the most annoying thing you will ever do, but thankfully you only have to do it once! ), is highly accurate and easy), and you will need to either learn how to use the hand controller to "Align GOTOs", or purchase a $40 EQDIR cable, use EQMOD, and completely computerize your process (HIGHLY recommended, you can buy BackyardEOS ($50) to greatly simplify your imaging sequences, and gain a lot of powerful features, such as highly precise live view focusing on your laptop or a windows 8 tablet, to get the best results.)


----------



## Click (Apr 4, 2014)

*Re: Deep Sky Astrophotography*



jrista said:


> I reworked my Rosette Nebula image with a new software package called PixInsight. A VASTLY superior product for astrophotography, it gives me so much more control over everything, and allows me to tweak specific layers and scales of detail independently without messing with my color balance. This version of Rosette is much more color accurate than the nearly monochrome-red version that I posted before...and it has a bit more color contrast, so certain details should be easier to see than before:



WOW Amazing shot 8) 8) 8)


----------



## Rienzphotoz (Apr 4, 2014)

*Re: Deep Sky Astrophotography*



jrista said:


> Hi Reinz. When it comes to astrophotography, the mount is pretty much the most important thing. Most astrophotographers who have even moderately diverse goals (i.e. just galaxies and nebula) are going to need to use multiple telescopes with different focal lengths, or at least one telescope with barlows and focal reduces, to get a field of view wide enough or narrow enough to frame their subjects properly. A good mount can last you for many, many years, where as telescopes (or, for that matter, camera lenses) usually come and go until you hit the real high end (i.e. 20" RCOS or PlaneWave telescopes).
> 
> For $1000, you can get yourself an entry-level mount. Something like the Orion Sirius, which is the little sibling of the Orion Atlas. The Sirius has a capacity of 30lb, which for visual is generally fine, but that pretty much equates to 15lb for astrography (the Sirius doesn't have the most sturdy tripod, so you REALLY have to stick to the 50% capacity limit for imaging work). That is practically nothing in terms of capacity, but if you just stick to your DSLR and lenses, it'll at least get you started.
> 
> ...


WOW, that's a lot of information ... I've copy pasted it on to my smartphone and will have to go over it at least a few times to get my heard around it ... I think it looks like I'll have to raise my budget to around $2000 ... thanks for the awesome info.


----------



## jrista (Apr 4, 2014)

*Re: Deep Sky Astrophotography*



Rienzphotoz said:


> WOW, that's a lot of information ... I've copy pasted it on to my smartphone and will have to go over it at least a few times to get my heard around it ... I think it looks like I'll have to raise my budget to around $2000 ... thanks for the awesome info.



Yeah, I would say $2000 will get you much farther. I spent just a little over $2000, on the Orion Atlas, a guiding setup, and a few accessories from ADM to help me mount it all. 

I HIGHLY recommend you look into BackyardEOS. You can do astrophotography with nothing but a cable release and bulb mode, but BYEOS makes things much, much easier. Especially focusing, it uses a tethered live view mode to show you, on your laptop screen (or a Windows 8 tablet, if you have that) what the camera sees through the lens. You can center on bright stars, and actually control the lens' focus (even if it's switched to manual) with BYEOS itself, and it offers some VERY fine control. You'll never be able to focus properly with just the viewfinder or just live view on the back of the camera, and getting focus right is pretty critical. 

BYEOS also lets you set up sequences, choose aperture, ISO, and exposure duration, mirror lockup, etc. You can set up multiple sequences in a single "program" to take multiple exposures of different durations as well, so you can create HDR images for scenes that might require it (say Orion Nebula or Andromeda Galaxy). It also lets you program sequences to take dark, bias, and flat frames (which you should research, as they are pretty essential). Taking darks, biases, and flats can be a real pain when you do it with a cable release, because you have to keep reconfiguring the exposure for different things. With BYEOS, you can just program HUGE sequences of darks, for example, spanning exposure times from 30 seconds to 600 seconds, and just let it run (which literally takes hours.) 

Anyway, with $2000 you'll definitely have enough to get started.


----------



## Don Haines (Apr 4, 2014)

*Re: Deep Sky Astrophotography*



jrista said:


> Hi Reinz. When it comes to astrophotography, the mount is pretty much the most important thing. Most astrophotographers who have even moderately diverse goals (i.e. just galaxies and nebula) are going to need to use multiple telescopes with different focal lengths, or at least one telescope with barlows and focal reduces, to get a field of view wide enough or narrow enough to frame their subjects properly. A good mount can last you for many, many years, where as telescopes (or, for that matter, camera lenses) usually come and go until you hit the real high end (i.e. 20" RCOS or PlaneWave telescopes).
> 
> For $1000, you can get yourself an entry-level mount. Something like the Orion Sirius, which is the little sibling of the Orion Atlas. The Sirius has a capacity of 30lb, which for visual is generally fine, but that pretty much equates to 15lb for astrography (the Sirius doesn't have the most sturdy tripod, so you REALLY have to stick to the 50% capacity limit for imaging work). That is practically nothing in terms of capacity, but if you just stick to your DSLR and lenses, it'll at least get you started.
> 
> ...



And to think that someone in another thread said "You are the small weak man, who attempts to compensate for your shortcomings by posting lengthy forum posts".... This is a wealth of information! Thank you for posting this, your posts have helped me many times since I joined the forum and this one is no exception.... I can't wait for a clear night to try out some of the things you have mentioned....


----------



## CarlTN (Apr 4, 2014)

*Re: Deep Sky Astrophotography*



Don Haines said:


> jrista said:
> 
> 
> > Hi Reinz. When it comes to astrophotography, the mount is pretty much the most important thing. Most astrophotographers who have even moderately diverse goals (i.e. just galaxies and nebula) are going to need to use multiple telescopes with different focal lengths, or at least one telescope with barlows and focal reduces, to get a field of view wide enough or narrow enough to frame their subjects properly. A good mount can last you for many, many years, where as telescopes (or, for that matter, camera lenses) usually come and go until you hit the real high end (i.e. 20" RCOS or PlaneWave telescopes).
> ...



He called me a weak man, stop siding with him and kissing his ass.


----------



## Don Haines (Apr 4, 2014)

*Re: Deep Sky Astrophotography*



CarlTN said:


> stop siding with him and kissing his ass.


He has helped me many times with advice on many subjects.... what have you done for me?


----------



## CarlTN (Apr 4, 2014)

*Re: Deep Sky Astrophotography*



Don Haines said:


> CarlTN said:
> 
> 
> > stop siding with him and kissing his ass.
> ...



I didn't realize you felt such hostility towards me. Do I have to do things for you in order to be treated with common decency? I don't recall disrespecting you, your opinions, or your photography. Sorry if you feel that way.


----------



## Don Haines (Apr 4, 2014)

*Re: Deep Sky Astrophotography*



CarlTN said:


> Don Haines said:
> 
> 
> > CarlTN said:
> ...



I feel no hostility towards you and I enjoy reading many of your posts and comments too.

I just wish you and Jrista wouldn't fight.. it detracts from everyone.


----------



## jrista (Apr 4, 2014)

*Re: Deep Sky Astrophotography*

@Don & @Reinz: I'm really glad to hear you guys are interested in astrophotography.  I think this is a GREAT time to get into the field...the technology we have today makes the cost of entry relatively low (if all you want to do is very wide field work, all you really need is a $800-$1000 mount, and your DSLR + lenses). If you find you really like it, high quality equipment can be purchased for only a few thousand dollars more, such as an astrograph OTA (like the AT8RC) and maybe an entry-level cooled astro CCD, the cheapest of which cost around $1500, about the same as a midrange DSLR.

The technology is pretty darn good, too. With an entry-level Atik CCD camera, people are producing high quality images that rival what NASA was getting a decade ago. Even highly advanced software packages for processing have become cheaper. It used to be that dedicated astro processing tools cost about $1000. Today, you can buy PixInsight, an extremely powerful processing system, for around $250.

Anyway, great time to be getting into astrophotography. I wish you guys the best, it's very fun (especially if your more technically minded, and enjoy a challenge.)


----------



## CarlTN (Apr 4, 2014)

*Re: Deep Sky Astrophotography*



Don Haines said:


> CarlTN said:
> 
> 
> > Don Haines said:
> ...



Sure seems that way to me, but you and him are old buddies, I guess I can understand that. There are some people that will never get along. I respect some of the work he does, and some of his knowledge, but I don't respect his hatred, anger, immaturity, antagonism, and self righteousness...he is deluded where I am concerned. He keeps claiming I don't know him. I say the same, he doesn't know me. All we know is what we read on here, and from day one (over a year ago) he has been extremely hostile and insulting to me...sending me insulting private messages. Nobody is perfect though. But I will not be called a small and weak man, and then have someone else portray me as the instigator in that exchange (as you did), because I was not. He started the name calling, and he got away with it. The moderators like him, they don't like me. I hope you can understand that. I certainly know you would not tolerate it, if it were directed at you. I refuse to be insulted for simply sharing my own experiences, by someone who has no experience with a product, yet types in caps as if to emphasize his pronouncements as "factual", and anyone who disagrees, is somehow in error. John Rista is not a god.


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## Don Haines (Apr 5, 2014)

*Re: Deep Sky Astrophotography*



jrista said:


> @Don & @Reinz: I'm really glad to hear you guys are interested in astrophotography.  I think this is a GREAT time to get into the field...the technology we have today makes the cost of entry relatively low (if all you want to do is very wide field work, all you really need is a $800-$1000 mount, and your DSLR + lenses). If you find you really like it, high quality equipment can be purchased for only a few thousand dollars more, such as an astrograph OTA (like the AT8RC) and maybe an entry-level cooled astro CCD, the cheapest of which cost around $1500, about the same as a midrange DSLR.
> 
> The technology is pretty darn good, too. With an entry-level Atik CCD camera, people are producing high quality images that rival what NASA was getting a decade ago. Even highly advanced software packages for processing have become cheaper. It used to be that dedicated astro processing tools cost about $1000. Today, you can buy PixInsight, an extremely powerful processing system, for around $250.
> 
> Anyway, great time to be getting into astrophotography. I wish you guys the best, it's very fun (especially if your more technically minded, and enjoy a challenge.)



I started with a really crappy 3" refractor telescope and got hooked!

I picked up a Celestron Advanced GT tracking mount... it's nice and solid and seems to track quite well. After lots of fiddling with aligning mounts, I ended up putting in some patio stones in the yard, made sure they were as level as possible, and marked where the tripod legs go... instant alignment! I have an 8" reflector telescope that I can use, or I have a mounting rail with a quick release camera mount. I have shot video of planets through the telescope, 2X barlow, and a 60D and run the images through Registax and I have just started to get interested in image stacking for nebulas...

The more I learn, the better the images get, and that just makes me want to try harder.

Backyard EOS seems like a perfect tool for capturing images of nebulas.... what software do you recommend for processing the images?

For planetary images, it's been recommended that I get a Celestron Neximage 5 CMOS Solar System Imager Camera to use instead of my DSLR... and I have been thinking of getting a 6D to replace my 60D for night skies... the 60D is real noisy!


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## Don Haines (Apr 5, 2014)

*Re: Deep Sky Astrophotography*



CarlTN said:


> Don Haines said:
> 
> 
> > CarlTN said:
> ...


I apologise for my comment. It was ill conceived and in poor taste. I hope we can move past it and be friends.


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## jrista (Apr 5, 2014)

*Re: Deep Sky Astrophotography*



Don Haines said:


> jrista said:
> 
> 
> > @Don & @Reinz: I'm really glad to hear you guys are interested in astrophotography.  I think this is a GREAT time to get into the field...the technology we have today makes the cost of entry relatively low (if all you want to do is very wide field work, all you really need is a $800-$1000 mount, and your DSLR + lenses). If you find you really like it, high quality equipment can be purchased for only a few thousand dollars more, such as an astrograph OTA (like the AT8RC) and maybe an entry-level cooled astro CCD, the cheapest of which cost around $1500, about the same as a midrange DSLR.
> ...



Ah! So your already into it. Great to hear! Is that a 60D, or the 60Da (just curious)?

I haven't tried planetary yet. I'm using my 600mm lens as a scope, and it isn't even remotely long enough to do planetary. Right now is pretty much the time for planets, though. At night, we have Jupiter, Mars, and Saturn all near their closest approaches to earth (I think Jupiter hit perigee in January, and Mars hits Perigee this month!) 

I just picked up a new contract, and it should pay decently. I may pick up the AstroTech AT8RC or AT10RC, to get myself an actual OTA that I can use a barlow with, and get a planetary imager. I don't want to miss the opportunity we have right now with all three planets high in the sky during the night. 



Don Haines said:


> Backyard EOS seems like a perfect tool for capturing images of nebulas.... what software do you recommend for processing the images?



For processing, I recommend you start with Photoshop. You should pick up Carboni's Astronomy Tools actions, and maybe Annies Astro Actions. These are practically essential, as they take otherwise complex, multi-step operations to help you stretch, denoise, deblotch, and enhance your images, and makes them "one click", effectively. Some actions might pop up some standard photoshop tools for input, but for the most part, these two action sets make up the core of the astrophotographers toolbox. At least, for DSOs they do.

Now, you do planetary, and planetary generally needs some different processing. I haven't looked too deeply for planetary processing actions, but I'm sure there are some out there. I'd look around, see what you can find. Ready-made actions really make the processing go faster, and are well worth the $20, $30, $50 you have to spend on them. 



Don Haines said:


> For planetary images, it's been recommended that I get a Celestron Neximage 5 CMOS Solar System Imager Camera to use instead of my DSLR... and I have been thinking of getting a 6D to replace my 60D for night skies... the 60D is real noisy!



I do recommend getting a proper solar system imager. However, in my research, a lot of Celestron's equipment turns out to be bottom rung. They make excellent OTAs, and their CGE Pro mount is quite good, however their guide camera and neximage imagers should probably be avoided. 

If you want a good planetary imager, I would look at QHY (http://qhyccd.com/en/left/page3/qhy5-ii-series/). They make a MUCH better imager, using Aptina sensors (high Q.E., high dynamic range). You could also look into the Starlight Xpress Lodestar (http://www.sxccd.com/lodestar-x2-autoguider). The Lodestar X2 was just announced, however it uses the new Sony ICX829 sensor, which is one of the most sensitive sensors on the market. The Lodestar has always been one of the most recommended guiding cameras, although it also works for planetary (IIRC)...the catch is that it is VERY expensive. Another option is the SBIG ST-i, which is also a guider and planetary camera. I like SBIG, Santa Barbara Instrument Group, good old "Made in the USA". Plus, I used to live very near Santa Barbara when I lived in California...kind of my old stomping grounds. The ST-i is more often used as an off-axis guider with the SBIG astro CCD cameras, but it is also a very good planetary imaging camera. It's cheaper than the Lodestar, but I think a little more expensive than the QHY.


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## Jack Douglas (Apr 5, 2014)

*Re: Deep Sky Astrophotography*

I think it's wonderful when whomever has the expertice, shares it. I'm learning a lot, for FREE. 

I think tactfulness is needed when being critical as no one likes to be put down and it's natural to feel slighted (although we shouldn't). A reminder to myself! 

Jack


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## CarlTN (Apr 5, 2014)

*Re: Deep Sky Astrophotography*



Don Haines said:


> CarlTN said:
> 
> 
> > Don Haines said:
> ...



Without a doubt, we can!

And I do apologize for responding in this thread in any case, as it was not all that necessary.


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## traingineer (May 31, 2014)

Well IOptron has release a new/kewl mount for astrophotography:

Skyguider, It uses similar components from the ZEQ25GT, lightweight, has an autoguider port and it's price is great.


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## privatebydesign (Jul 11, 2014)

Just read about this, 

http://news.yale.edu/2014/07/10/hi-ho-astronomers-discover-seven-dwarf-galaxies

http://dunlap.utoronto.ca/instrumentation/dragonfly/

that should keep you Canon shooting astro guys happy for a bit..............


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## traingineer (Jul 11, 2014)

privatebydesign said:


> Just read about this,
> 
> http://news.yale.edu/2014/07/10/hi-ho-astronomers-discover-seven-dwarf-galaxies
> 
> ...



Thanks PBD, that's some pretty cool news!


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## NancyP (Jul 16, 2014)

Deep sky astrophotography is a continual learning process, makes the geeky heart happy! All manner of post-processing computational strategies out there, lots of discussion (Cloudy Nights a worthy forum to follow, as are AP software user fora).


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## Johnmb1 (Apr 4, 2015)

I have been researching the iOptron Skytracker for doing some Milky Way photography. Not sure what kind of deep sky images I will get. Any comments will be geatly appreciated. The gear I'd be using are a Canon T1i, Tokina 11-16 f/2.8 wide angle lens and a Tamron SP 70-300 zoom. Thanks for any input.


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## jrista (Apr 9, 2015)

Hi John,


The wide angle lens is probably fine for big expansive milky way imaging. The zoom, on the other hand, I would stay away from. Longer zooms are never very good for astrophotography...too many tradeoffs have to be made for a zoom to be effective for daytime photography, and the demands of astrophotography are significantly more stringent. You could stop down, but you would likely have to stop down considerably to eliminate CA or other optical aberrations. Your probably much better off picking up a decent refracting APO telescope, and getting the required adapters to attach your Canon DSLR to it.


You could learn how to do astrophotography with the Tamron SP, as there are plenty of mechanical and operational things you will need to sort out before you really get into the more serious side of astrophotography, and it can take a while to sort all those things out. There is also control software to consider, and things like that. So while the IQ may not be good, the 70-300 could at least let you get your feet wet while you consider better options.


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## telemaq76 (Sep 9, 2015)

andromeda galaxie
with canon 1dx+400 5.6+ioptron skytracker


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## scyrene (Sep 9, 2015)

telemaq76 said:


> andromeda galaxie
> with canon 1dx+400 5.6+ioptron skytracker



Excellent work!


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## Jack Douglas (Sep 10, 2015)

Johnmb1, I bought the skytracker but haven't used it much. It is tricky to get the alignment but not impossible and the unit is well made. All you get is longer image times without star trails. The tripod has to be rock solid. In my case I have adapted my Jobu gimbal head to the unit and find that to be a nice asset when everything is balanced. As the city expands in my direction I'm getting more light pollution and haven't made the effort to get away from it - so many plans and so little accomplished!

I wish I were jrista! 

Jack


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## telemaq76 (Oct 21, 2015)

new picture of andromeda galaxie, with canon 1dx+500f4+skywatcher neq6pro mount
57 x 120 sec +DOF


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## Click (Oct 21, 2015)

Great picture, telemaq76.


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## Northstar (Oct 22, 2015)

telemaq76 said:


> new picture of andromeda galaxie, with canon 1dx+500f4+skywatcher neq6pro mount
> 57 x 120 sec +DOF



That's a really cool photo! If I had created it, I'd be proud. Nice!


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## telemaq76 (Oct 24, 2015)

thank you guys !


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## East Wind Photography (Oct 24, 2015)

Jack Douglas said:


> Johnmb1, I bought the skytracker but haven't used it much. It is tricky to get the alignment but not impossible and the unit is well made. All you get is longer image times without star trails. The tripod has to be rock solid. In my case I have adapted my Jobu gimbal head to the unit and find that to be a nice asset when everything is balanced. As the city expands in my direction I'm getting more light pollution and haven't made the effort to get away from it - so many plans and so little accomplished!
> 
> I wish I were jrista!
> 
> Jack



If you happen to have one of the big whites with the drop in filter, you can order a 48mm or 2 inch deep sky filter and it will fit the filter holder. It buys you a stop or two in light polition reduction for most nebula. There are also filters that drop into the mirror box of your camera which can help.

I use the skywatcher star adventurer becuase its simple. I can get away with using my 300mm f2.8 on it but i only grt about 50% useable shots with that weight. Still its far better than not getting anythig at all if the equipment is too big and complex to set up that you never do. Ideally you should target a mount or tracker that is twice the load bearing capacity when all of your gear is mounted on it.


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## Jack Douglas (Oct 24, 2015)

East Wind Photography, thanks for that advice. The 300 2.8 II is definitely excessive for my little tracker but with the gimbal and perfect balance and a remote release it actually is manageable. Adding 1.4X in there doesn't add much weight either. However, my biggest challenge is getting alignment that is adequate and _figuring our where to aim_, since I don't have any previous background in this realm. Not to mention that just touching the unit with that weight tends to shift things. I don't suppose my polarizing filter for the 300 would help??

The 70-200 2.8 II is quite a bit more realistic for my setup. I've been having some health issues in recent years and have found this somewhat awkward night photography (often in the cold) a bit discouraging to learn at my age. Any advice (or maybe an excellent book) regarding the various challenges you can visualize me facing?

Jack


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## jrista (Nov 1, 2015)

For a 300mm f/2.8 lens, you need more than just a tracker. You need a full equatorial mount. Your going to experience far too much periodic error from the mount (likely 30 arcseconds or so, which WILL affect the quality of your data), and probably shake or vibration due to the high payload. A 300mm f/4 would probably be fine on a tracker, but an f/2.8 is just...huge. I wouldn't consider anything less than the Orion Sirius for something like that.

You would likely need to guide for subs over about 2 minutes as well, which requires a companion laptop, software, etc. 



Jack Douglas said:


> Johnmb1, I bought the skytracker but haven't used it much. It is tricky to get the alignment but not impossible and the unit is well made. All you get is longer image times without star trails. The tripod has to be rock solid. In my case I have adapted my Jobu gimbal head to the unit and find that to be a nice asset when everything is balanced. As the city expands in my direction I'm getting more light pollution and haven't made the effort to get away from it - so many plans and so little accomplished!
> 
> I wish I were jrista!
> 
> Jack



It just takes practice.  

City light pollution expansion, however, is a serious problem. My dark site, last December, was measuring over 21.6mag/sq"...very, very dark. Lately it's been measuring 21.1mag/sq", and sometimes even lower than that. That is over a stop difference in exposure (1.6x more sky brightness, or requiring about 1.2 stops shorter sub exposures), which reduces contrast a good deal. 

It's amazing, when you see the Milky Way at an exceptional dark site, where it is so freaking dark that the landscape around you is nearly pitch black, but the milky way is so insanely bright that it actually causes your body to cast a faintly visible shadow on the ground. That is how the night sky is supposed to be....and sadly, just as with so many other things, we have completely and utterly destroyed that with another form of pollution. You cannot even see the milky way at all in the city, or even near the city, which is so truly sad.


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## Jack Douglas (Nov 1, 2015)

Jon, thanks for the feedback.

Jack


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## jrista (Nov 3, 2015)

Thought you guys might like to see the new (heh, "new"...I bought it back in March, haven't had a chance to really use it until now) AstroTech 8" Ritchey-Cretien telescope and Moonlite focuser:












This is a 1625mm telescope, 203mm aperture, f/8. High resolution scope. Parabolic mirror design, although I am using a TS field flattener for RC's with it. Between the flattener ($360), an off-axis guider module ($300), the scope ($1100) and the moonlite focuser ($800), as well as about $200 worth of various other accessories, this is almost a $2800 project that I bought and paid for over six months ago, and was only really able to use properly for the first time tonight.  (Thanks, El Ninio! ) 

Still using the 5D III for the time being, but damn, that is one helluva noisy camera. Going to be getting a CCD camera soon here, which will replace the 5D III for high resolution imaging. I may keep using the 5D III for doing wide field imaging with the 600mm, or I may get some other astro modded DSLR or mirrorless that I could use for that (probably a 6D, only because Sony's SDK is still a bit lackluster and software support is a ways out.) I'll definitely be using the 5D III with some new Samyang lenses and a Star Adventurer tracker I picked up recently for some ultra wide field work. The Samyang lenses are mind bogglingly good, optically anyway, for the price. Almost perfectly flat fields, center to corner, which is something neither Canon, Nikon nor Zeiss have ever quite achieved. (Of course, the Samyangs are totally manual and lack even the most basic electronic connection to the camera.)


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## meywd (Nov 3, 2015)

jrista said:


> Thought you guys might like to see the new (heh, "new"...I bought it back in March, haven't had a chance to really use it until now) AstroTech 8" Ritchey-Cretien telescope and Moonlite focuser:
> 
> 
> 
> ...



Congratulation.....on starting to use it , would like to see direct comparison with the 600mm if that's even possible, but I know that reflectors and refactors aren't the same, though I keep forgetting the difference, regarding the cost, whats the total cost including the tracker?

Also which Samyangs do you plan to get, maybe you should wait until the reviews of the Sigma 20mm Art.


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## jrista (Nov 5, 2015)

Thanks. Night two, still figuring some things out. This thing catches even the slightest bit of wind like a sail, so keeping it tracking accurately is pretty tough. Not sure what I'm going to do about that...the longer the scope, the more sensitive it is to unwanted motion, and this thing is pretty sensitive to just about everything. Even me walking around the mount affects the guiding (need to build myself a pier so I can avoid that problem.) 

This is an f/8 scope, so four times less light per unit time than my 600mm f/4. It really shows. I'd use 270-300 second (4m30s - 5m) exposures with the 600mm...I am already using 1200 second (20m) exposures with this thing, and those are barely sufficient. And that is with all the light pollution in my back yard...I can't imagine what it would be like using this thing at a true dark site...I'd probably be using 30-40 minute subs!

Well, anyway. On the Samyang front, I've got the 14mm f/2.8 ED, and the 135 f/2 on the way. The Samyang 14 f/2.8 is amazing. Near-pinpoint stars right into the corner. Ideal for ultra wide field milky way shots. Thing is, it's so freaking wide, that you get field rotation in a matter of seconds if you are not tracking, so it wouldn't be very useful for untracked tripod-only imaging. The 135mm won't have the field rotation problem, but because it's so much longer, it too still requires tracking. Both are excellent for astro, but they are otherwise basic, manual only lenses. For me, that's fine, my only use cases are landscape, astro and possibly some close up photography where I manually focus anyway. I may get the Samyang 85mm f/1.4 as well...I've seen some portraiture shots with that...amazing boke,very sharp. I'm very impressed with the optical quality of these otherwise extremely cheap lenses.


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## scyrene (Nov 5, 2015)

jrista said:


> Thanks. Night two, still figuring some things out. This thing catches even the slightest bit of wind like a sail, so keeping it tracking accurately is pretty tough. Not sure what I'm going to do about that...the longer the scope, the more sensitive it is to unwanted motion, and this thing is pretty sensitive to just about everything. Even me walking around the mount affects the guiding (need to build myself a pier so I can avoid that problem.)



Simple: build an observatory for it!


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## Jack Douglas (Nov 5, 2015)

Isn't that how it always seems to go as we dig ourselves deeper and deeper into a money pit! I have a friend who did in fact build an observatory that is very impressive and he gets a lot of pleasure out of using it.

Jack


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## Don Haines (Nov 5, 2015)

scyrene said:


> jrista said:
> 
> 
> > Thanks. Night two, still figuring some things out. This thing catches even the slightest bit of wind like a sail, so keeping it tracking accurately is pretty tough. Not sure what I'm going to do about that...the longer the scope, the more sensitive it is to unwanted motion, and this thing is pretty sensitive to just about everything. Even me walking around the mount affects the guiding (need to build myself a pier so I can avoid that problem.)
> ...



I know of several astronomy "enthusiasts" who have done that..... pour a cement pad ( I think she said it was 4 feet thick!), build an 8x8 "shed" with a roof on hinges..... Just head out to the yard, open it up, and away you go......


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## telemaq76 (Nov 7, 2015)

hello guys i need your help . I m using a canon 500 f4 IS I and i m looking for filter to shoot under light pollution. I readed we can find some filters to fit in the drop filter of big white, like the IDAS LPS-V4 . it s hard to find information about it. Can you confirm ant tell me what size to buy, 52mm i guess. Any idea where i can buy this? a picture of the filter in the drop filter would be great. I barely undertand how to install it, according to the pictures of the filter i see on the web


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## scyrene (Nov 7, 2015)

telemaq76 said:


> hello guys i need your help . I m using a canon 500 f4 IS I and i m looking for filter to shoot under light pollution. I readed we can find some filters to fit in the drop filter of big white, like the IDAS LPS-V4 . it s hard to find information about it. Can you confirm ant tell me what size to buy, 52mm i guess. Any idea where i can buy this? a picture of the filter in the drop filter would be great. I barely undertand how to install it, according to the pictures of the filter i see on the web



I don't know about that filter specifically, but yes, you can put some small filters in there. I think people recommend slim 52mm ones. I have an Astronomik filter that's meant to go inside an APS-C Canon body, between the mirror and the lens, but it fits into the drop-in filter perfectly - I just place it against the glass and tape it down.


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## telemaq76 (Nov 7, 2015)

and it does not move? i shoot with full frame camera but in your opinion i can buy an apsc cls filter and intall it in drop in filter?


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## JMZawodny (Nov 7, 2015)

telemaq76 said:


> hello guys i need your help . I m using a canon 500 f4 IS I and i m looking for filter to shoot under light pollution. I readed we can find some filters to fit in the drop filter of big white, like the IDAS LPS-V4 . it s hard to find information about it. Can you confirm ant tell me what size to buy, 52mm i guess. Any idea where i can buy this? a picture of the filter in the drop filter would be great. I barely undertand how to install it, according to the pictures of the filter i see on the web



I use the 52mm IDAS LPS-P2 with very good results.


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## telemaq76 (Nov 7, 2015)

JMZawodny said:


> telemaq76 said:
> 
> 
> > hello guys i need your help . I m using a canon 500 f4 IS I and i m looking for filter to shoot under light pollution. I readed we can find some filters to fit in the drop filter of big white, like the IDAS LPS-V4 . it s hard to find information about it. Can you confirm ant tell me what size to buy, 52mm i guess. Any idea where i can buy this? a picture of the filter in the drop filter would be great. I barely undertand how to install it, according to the pictures of the filter i see on the web
> ...



ok thanks but how to you install it? is it not a spin-on filter?


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## JMZawodny (Nov 7, 2015)

telemaq76 said:


> JMZawodny said:
> 
> 
> > telemaq76 said:
> ...



Yes it is. The filter unscrews from the frame (at least it does on the ones I have). Did you buy the lens are are you renting/borrowing it? I believe both my 400mm and 300mm lenses came with a spare (it was long enough ago that I could be mistaken). I also have one that can be rotated from the outside for use with a CP.


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## JMZawodny (Nov 7, 2015)

You very likely need one of these Drop in filter holders.
http://www.bhphotovideo.com/c/product/186092-REG/Canon_2612A002_Drop_In_Filter_Holder_for.html


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## telemaq76 (Nov 7, 2015)

JMZawodny said:


> You very likely need one of these Drop in filter holders.
> http://www.bhphotovideo.com/c/product/186092-REG/Canon_2612A002_Drop_In_Filter_Holder_for.html



i bought the lens. you mean i have to buy a second filter holder ? I can t use the one i have in the lens?
by any chance do you have a picture of the filter holder with the astro filter on it?


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## JMZawodny (Nov 8, 2015)

telemaq76 said:


> JMZawodny said:
> 
> 
> > You very likely need one of these Drop in filter holders.
> ...



Here is a pic of the 3 different versions that I own.


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## telemaq76 (Nov 8, 2015)

ok thank you so much, i think i understand, then i need new filter holder with no filter inside and astro 52mm filter


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## garret (Nov 8, 2015)

> Also which Samyangs do you plan to get, maybe you should wait until the reviews of the Sigma 20mm Art



No the Sigma 20 mm 1.4 Art is not good for astrophotograpy, see here : http://www.lenstip.com/457.7-Lens_review-Sigma_A_20_mm_f_1.4_DG_HSM_Coma__astigmatism_and_bokeh.html


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## East Wind Photography (Nov 8, 2015)

telemaq76 said:


> JMZawodny said:
> 
> 
> > You very likely need one of these Drop in filter holders.
> ...



I bought an extra drop in filter holder used (didn't care about the quality or the glass)..not the screw on. The problem is most filters are.too thick to fit back into the camera. I bought the one with the flip up gel holder. There is a retainer ring that holds the glass filter in. I just swapped it with my deep.sky filter. Works like a champ.


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