# Creating star trails.



## Valvebounce (Mar 13, 2015)

Hi Folks. 
A couple of my friends and I wish to have a go at creating some of those images with the deliberate star trails, this weekend looks like the weather and moon might play ball, moonrise after midnight, we have a reasonable dark sky to go to, weather clear, but cold..... Why are we doing this... 
Anyway, I have searched the forum, and all except one of the star trail references seem to lead to how to avoid them, not much help when that is what you are setting out to get! 
I wonder if a couple of you good folks could give me a few pointers, direction to point, I assume we need the pole star in the middle to create a circular trail, keep the horizon or not, approximate exposure time, ISO 100? 
Keeping the horizon will probably preclude including the pole star so are the trails more linear along the horizon? 
Thanks for any help with this. 

Cheers, Graham.


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## climber (Mar 13, 2015)

Hi.

This is one of my recent shot. It is stack of 230 images (for the sky) at 30s, f/2.8, ISO 400. It is "panorama" of two frames, one above another. The first for the sky with little bit of mountains and another one (single exposure) for the landscape below. All shots were horizontal.

I prefer shooting star trails when the moon is "big". Because the landscape will be better illuminated. In my case, if there is no moon, the mountains are not visible at all. On a days when there is no moon, I prefer shooting milky way.

When you shoot a sequence of 30s exposures, you will see that there are a small gaps between each exposure (in star trails). You can resolve this using StarStaX program, which has so called "Gap Filling" option, but using this it is much harder to erase trails of the airplanes. I rather use Photoship with its "Lighten" blending mode. In that case it is very easy to erase trails of the airplanes. You only have to paint them in black. Because you are in "lighten" mode, the black painting will not be visible.
And then how I resolve "Gap" problem. I use some sort of a blurring filter. Like in this case, where motion is circular, I used "Spin Blur" in Filter Gallery. It nicely blurs the startrails and fills the gaps.

Hope it helps just a little bit


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## Valvebounce (Mar 13, 2015)

Hi climber. 
Thank you for your help. I'm afraid that I'm not that good with software, and my friends are terrible, and they would probably say themselves, worse than terrible at using a computer! I was hoping for a one shot solution, some minutes as I saw on one post here, something like 15 mins? Then with some coaxing I can get the guys to process with DxO, thanks to its easier automatic approach! 
I see where your coming from with the moonlight, I was thinking of starting in the fading light of dusk to get the scenery. 
Edit, slipped my mind to mention, very nice picture, thanks for some more inspiration. 

Cheers, Graham. 



climber said:


> Hi.
> 
> This is one of my recent shot. It is stack of 230 images (for the sky) at 30s, f/2.8, ISO 400. It is "panorama" of two frames, one above another. The first for the sky with little bit of mountains and another one (single exposure) for the landscape below. All shots were horizontal.
> 
> ...


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## climber (Mar 13, 2015)

With 15 min exposure you will probably get overexposed landscape (foreground). Unless there is no complete darkness. If you stack several photos in "lighten" mode, the end result will be as bright as the brightest image.


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## Valvebounce (Mar 14, 2015)

Thanks climber, another valid point, I guess some experimentation is in order, I think we will have a couple of hours at least to figure something out, a bit like when I took the pictures of the Hoegh Osaka when she fell over I the dark, take a guess, check the result, have another go! 

Cheers, Graham. 



climber said:


> With 15 min exposure you will probably get overexposed landscape (foreground). Unless there is no complete darkness. If you stack several photos in "lighten" mode, the end result will be as bright as the brightest image.


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