Dark frames producing very odd results in DSS and Pixinsight

[MrNelz]

Hello all,

I'm having a bit of a mare with DSS and Pixinsight when stacking. Usually when I stack my images they look like this with an unlinked stretch in PixInsight.

Ignore the terrible coma at the edges of the first image as that's not the issue here and has since been corrected

The last couple of sessions my stacks end up looking like this, this post stretch by the way..........

And with a more aggressive stretch

Now if I remove the dark frames and run the satck again........

Steps I have tried to fix the above

1. Ensure stack settings in DSS match my old images

2. Take a new dark library

3. Stack and integrate in PixInsight

The first 2 images were fresh stacks of the old data, using my new dark files.

All of the above steps have produced the same result. The only change since the first 2 images is I've moved house. I have retaken the dark library here, same settings as I always use (-10C, Gain 120). I've never come across this issue before. Any ideas? I'm stumped....

Equipment:

ASI294MC-Pro

 

 

Edited August 20, 2023 by MrNelz

[teoria_del_big_bang]

Hello,

Forgive me but I am still a little confused even after reading your OP a few times.

You say "The first 2 images were fresh stacks of the old data, using my new dark files." and these two images auto-stretch in Pi perfectly okay, which would indicate the darks are not the issue - or have I missed something there ?

But also you say for the 2nd two images, that do not auto-stretch to reveal anything, if the SAME dark master is used but if you stack them without the dark master then the auto-stretch does reveal the nebula. Again have I understood that correctly ?

There should be no need to take new dark library just because you moved house - a dark library is usually used to make a dark master and that dark master can be used for 6 to 12 months without issue and then maybe take a new dark library and make new masters every 12 months or so, well that's what I do anyway .

I think to get anywhere you need to upload a link to your dark frames, dark masters and your light frames and ideally a flat master if you are using one.

Steve

[MrNelz]

Hi Steve,

Yes you have got it bang on. Hence why I'm so confused!!! This has happened after my last 2 sessions up here now. Managed to just stack the lights with no calubration frames at all on the first sesh then edit out the amp glow, hot/cold pixels by hand in PI and PS but that was one hell of a task!!

What's the best way to upload the darks/flats/lights? Dropbox/google drive?

Thanks for the prompt reply

[teoria_del_big_bang]

18 minutes ago, MrNelz said:

What's the best way to upload the darks/flats/lights? Dropbox/google drive?

Yes but don't ask me how, I can do it but always takes me a while to figure how each time.
I assure you i am no expert on processing but use PI a fair bit and if i cannot answer there are plenty of experts on SGL that can 🙂 

Steve 

[MrNelz]

****UPDATE****

I've just built another set of dark frames (Strangely at -8C as the cooler was struggling in today's heat) and lo and behold we're back in the game......really not sure what the hell happened there. If any nerds have any ideas that'd be great.

[bomberbaz]

On 20/08/2023 at 11:03, MrNelz said:

****UPDATE****

I've just built another set of dark frames (Strangely at -8C as the cooler was struggling in today's heat) and lo and behold we're back in the game......really not sure what the hell happened there. If any nerds have any ideas that'd be great.

 

I have somehow managed to replicate your problem, solved it in the identical way. 

What are you using by way of controller to capture the imaged. I am using the ASI Air+

Steve