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What's gone wrong here?

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#1 osbourne one-nil

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Posted 05 August 2021 - 06:08 AM

I took 30x20 second exposures of the Summer Triangle region last night, with my 16mm lens, and stacked them in Deep Sky Stacker using mosaic mode. It's resulted in awful distortions around the edge. Is this because 20 seconds is pushing it at 16mm, or simply that stars trail more around edge and there's nothing to be done? 

 

 

1500 milkyway copy.jpg



#2 osbourne one-nil

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Posted 05 August 2021 - 06:10 AM

I much prefer the single frames, certainly around the edges anyway. Perhaps stacking is only useful for the central portions of these sort of shots?

 

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#3 happylimpet

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Posted 05 August 2021 - 09:12 AM

So you weren't tracking? If im right, then you need to make sure you select one of the higher orders of aligment, which is bicubic i think, to account for the distortion of the lens. EVen that might not be enough. You'll also need to have stars detected right up to the corners - ie lots!

 

There's no reason this cant be stacked in theory.


Edited by happylimpet, 05 August 2021 - 09:13 AM.


#4 osbourne one-nil

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Posted 05 August 2021 - 10:26 AM

Thanks - I'll give that a go. I think I selected 175 stars to be aligned. I'll pump that figure up and see what happens!



#5 osbourne one-nil

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Posted 05 August 2021 - 10:39 AM

Hmmmm - not to worry! This was bicubic and aligned with 3000 stars. 

 

1500 milkyway2 copy.jpg



#6 KLWalsh

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Posted 05 August 2021 - 10:55 AM

I’ve never tried Sequator, but I’ve heard that some people use it for stacking nightscape and milky way photos taken with a standard tripod and camera arrangement.
You might take a look at it.
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#7 osbourne one-nil

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Posted 05 August 2021 - 01:48 PM

Brilliant - thank you! Another option is getting my camera mounted to my EQ mount and going that route too. 

 

Normally I like to combine the starscape with some silhouetted foreground so I wouldn't try to stack anyway, but I like to know the theory!




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