Numpty question about stacking from different sessions

[kirkster501]

^^^^

So lets say I have exposures from different sessions, maybe without an *exact* field match and maybe different exposures. How does one go about stacking such images please? Do you just pile the individual subs all into the stacking software and let it sort them out? Or does one process each individual session data as per usual and create a resultant stacked image from lights, darks etc (no tinkering with PS) and then stack multiple such complete images to give a "sum of" master image comprised of all the individual image sessions' images?

That make sense?

Reason I ask is that surely don't have to keep starting each picture of an object from scratch every night? That's what I have been doing... Lets say I get two hours on an object one night each of a certain length exposure. The next time when I set up and I will never get the object 100% exactly framed the same as the night before. And also, due to lighting conditions I may need to have different exposures too.

Thanks, Steve

[nmoushon]

Not sure what program you use but in DSS you take one session worth of subs (lights, darks, bias, flats) and load them in like normal. Then go down near the bottom of the window part of DSS where is shows you all your subs listed and theres a tab/button the says "New Group" (or something like that). Then take your second session (lights, darks, bias, flats) and load them up like you did the first session. The repeat for how many different sessions you do. Different ISO, rotation, slightly off center from last session doesn't matter. DSS will figure it out and allign and stack them all up. You wont have clean edges so in the processing you will want to rotate and crop your picture to how you want it. Make sure to do this first and not last because those edges effect the histogram and can throw you off a little.

[kirkster501]

Not sure what program you use but in DSS you take one session worth of subs (lights, darks, bias, flats) and load them in like normal. Then go down near the bottom of the window part of DSS where is shows you all your subs listed and theres a tab/button the says "New Group" (or something like that). Then take your second session (lights, darks, bias, flats) and load them up like you did the first session. The repeat for how many different sessions you do. Different ISO, rotation, slightly off center from last session doesn't matter. DSS will figure it out and allign and stack them all up. You wont have clean edges so in the processing you will want to rotate and crop your picture to how you want it. Make sure to do this first and not last because those edges effect the histogram and can throw you off a little.

Many thanks. Got it! Never realised this. Also, say you have a stack of 10 min subs. IF you then stack these with, say, 3 min subs are you detracting or "wasting" the quality of the ten min subs?

Is there a best practise about what to combine with what?

Thanks, Steve

[nmoushon]

Many thanks. Got it! Never realised this. Also, say you have a stack of 10 min subs. IF you then stack these with, say, 3 min subs are you detracting or "wasting" the quality of the ten min subs?

Is there a best practise about what to combine with what?

Thanks, Steve

I've never made different groups for different sub lengths. Just different sessions. I don't believe it (90% sure it doen't).

Oh I made a mistake above and saying ISO doesn't matter. I meant to say length doesnt matter. ISO does matter. If you have different ISO setting, even in the same night, I always but them in seperate groups.

[Gina]

I've always put all the L subs together in DSS and same for the R, G and B and never used groups so far. I guess I ought to find out about groups, I may be missing out I align and resize LRGB with RegiStar.

[kirkster501]

I've always put all the L subs together in DSS and same for the R, G and B and never used groups so far. I guess I ought to find out about groups, I may be missing out I align and resize LRGB with RegiStar.

Hi Gina, so you put all the subs together of the same type (L,R,G,B etc) even if they are of different exposures?

[Gina]

Hi Gina, so you put all the subs together of the same type (L,R,G,B etc) even if they are of different exposures?

Yes.