Stacking stacked photos

[Rob20236]

Hi all. 

As title can you stack allready stacked photos.

Story goes, as I don't have a garden and don't get out much for long sessions at night due to work the next day, I have to make the most of any clear skies we have, I shoot from my skylite so I dismantle my scope after every shoot. So after every session I take my calibration frames then stack them. 

If by chance the following night is clear I repeat the process. So my question is if I shoot the same target can I stack my allready stacked frames? Or should I just stack all the raw files together?

Will the flat frames be useless for stacking all the raw files together as I've dismantled my scope after every session?

Sorry to go on. And thank you advance for any advice

[The Lazy Astronomer]

Stack all the raw files together. If your equipment is relatively dust-free then you could probably get away with reusing the flats from the previous session. If you've got a few dust motes visible in the image then take flat frames for each session. 

When you're stacking, tell the software to associate lights from night 1 with flats from night 1, lights from night 2 with flats from night 2, and so on. 

What software are you using to stack?

Edited April 15, 2021 by The Lazy Astronomer
Typo

[Rob20236]

Thank you for reply. 

I use deep sky stacker on pc. Can you associate different night photos on dss? (On way to look into it now).

I do generally try to keep my equipment dust free but of the 3 nights I've managed to get photos I noticed the second nights flat frames had noticeable dust motes.

Thank you again

[Thorney]

I may be wrong on this but once you load all your images into DSS from the first night there will be a tab at the bottom to make another group. Then load your images from the second night into that group and so on.   

[The Lazy Astronomer]

35 minutes ago, Thorney said:

I may be wrong on this but once you load all your images into DSS from the first night there will be a tab at the bottom to make another group. Then load your images from the second night into that group and so on.   

This is exactly right. I think though, that anything in the 'main' tab is applied to all of the other groups, although I may be wrong. I usually just put my darks in the main group and then put the lights and relevant calibration frames in their respective groups.

[Rob20236]

perfect.

thank you both. you are an arcturus 😉 🌟