Stacking over several nights

[edarter]

Hi,

Whats the accepted best practice for stacking when you have data from several evenings?  I gathered lights, darks and bias on each evening, so do I stack each evenings data as completely separate sets and then stack the resulting unedited images together ready for post processing? Or mash em' all in to one stacking marathon together? I'm using DSS for stacking btw.

Thanks
Ed

[Atreta]

Since you have calibration files for each session, in DSS you can place the images in different groups, for instance you load the first night's images it will be in the main group tab(right in the bottom of the screen) and it will create a group 1 tab, you put the second session there along with its proper calibration files, thenit will create a group 2 and so on. 

But if you use only one set of calibration files you can load them all together in the same group. 

Edited April 1, 2020 by Atreta

[edarter]

Do the groups get treated separately then? And does it attempt to stack the groups together once they are all done individually?

 

[Atreta]

Yes each group will be processed in separate , but there will be only one final stacked image. 

Edited April 1, 2020 by Atreta

[Adam1234]

54 minutes ago, Atreta said:

Yes each group will be processed in separate , but there will be only one final stacked image. 

I heard that any calibration files in the main group get applied to all groups? 

[Notty]

12 hours ago, Adam1234 said:

I heard that any calibration files in the main group get applied to all groups? 

I believe that Is correct. Don’t know it’s it’s how everyone does it but in the main group I just put my reference image and master dark. Subsequent groups have the lights and calibrated flats for each night/channel

[Atreta]

18 hours ago, Adam1234 said:

I heard that any calibration files in the main group get applied to all groups? 

Nice, didn't know that.

Edit: I just read the information at dss site and you are right, thanks for pointing it out.

Edited April 2, 2020 by Atreta

[Adam1234]

3 hours ago, Atreta said:

Nice, didn't know that.

Edit: I just read the information at dss site and you are right, thanks for pointing it out.

I only found this out last week myself. I got advised to put any calibration frames which can be applied to all groups (such as bias frames) in the main group, then the lights in the subsequent groups with their specific calibration frames. Thought, because I've just started using flats and flat darks, taking both of these on the night, not entirely sure what to do now and also been advised not to use bias if I'm using flat darks...🤔

[edarter]

hmm... so does this mean you should only put global calibration files in the first group (no lights) and then use subsequent groups for lights and their specific calibration frames??
 

[Adam1234]

3 hours ago, edarter said:

hmm... so does this mean you should only put global calibration files in the first group (no lights) and then use subsequent groups for lights and their specific calibration frames??
 

Yes I believe so. These threads may help

 

http://www.astronomyforum.net/astrophotography-image-processing-forum/146105-how-do-you-stack-images-different-nights-2.html

Adam

[Adam1234]

.

 

Edited April 3, 2020 by Adam1234

[Adam1234]

This should help as well, I've not watched it myself yet, only just found it, but will watch it later