Stacking images from future nights in dss

[Chefgage]

Hello all. Searched through the threads but could not find the answer to this.

I can stack my lights, flats and darks from two different nights in dss and process them in pixinsight. I know how to do that. But for example if I want to keep adding to  this project how is it best to add more data to the project using dss?

I have a cooled camera (294mc-pro) so I can have a dark library. I take all my subs at the same exposure. So let's say a few weeks later I take some more data (lights and flats) that I want to add to the project. Is it best to just re-stack the images using the group tabs in dss (darks in the main group to calibrate across all groups) for ALL the data (the original data plus the new data). 

I don't want to stack the stacks. I understand I will be re-processing the data which is good as it gives me a comparison between the processed image of the first two nights and the new image contains the new data.

Edited January 28, 2022 by Chefgage

[Adam1234]

Unsure if there would be an issue stacking stacks or not. I would probably recommend just re -stacking all of the original files plus the new ones. 

If you re-use the same darks and flats across the sessions (provided the set temperature on your camera is the same across sessions and you keep tye camera attached to the scope) you can just put everything in the same group in DSS.

Just out of interest, is there any reason why you don't do your calibration/registering/stacking in PixInsight?

Edited January 28, 2022 by Adam1234

[Chefgage]

1 hour ago, Adam1234 said:

Unsure if there would be an issue stacking stacks or not. I would probably recommend just re -stacking all of the original files plus the new ones. 

If you re-use the same darks and flats across the sessions (provided the set temperature on your camera is the same across sessions and you keep tye camera attached to the scope) you can just put everything in the same group in DSS.

Just out of interest, is there any reason why you don't do your calibration/registering/stacking in PixInsight?

The reason being I have not got round to learning how to do it in pixinsight. I really need to get on with that. 

[smr]

What I do is name a folder 'Horsehead and Flame Nebula' for example and then within that folder make sub folders for each night - named by date, ie. 28-01-22, within that I make sub folders, Lights, Darks, Flats and Dark Flats

I then put all those images from all four sub folders into Group 1 in DSS, and for the next night of imaging I'll put all the images from that night into Group 2 etc.

[Chefgage]

1 hour ago, smr said:

What I do is name a folder 'Horsehead and Flame Nebula' for example and then within that folder make sub folders for each night - named by date, ie. 28-01-22, within that I make sub folders, Lights, Darks, Flats and Dark Flats

I then put all those images from all four sub folders into Group 1 in DSS, and for the next night of imaging I'll put all the images from that night into Group 2 etc.

So for example then for two nights of imaging you would use group 1 and group 2 tabs and then process as normal. If say a couple of weeks later you get another night on that same target would you then re-stack everything i.e. put the first nights lights,darks,flats,bias in group 1, second night in group 2 and the new data in group 3 and then re-stack?

Edited January 28, 2022 by Chefgage

[smr]

Just now, Chefgage said:

So for example then for two nights of imaging you would use group 1 and group 2 tabs and then process as normal. If say a couple of weeks later you get another night on that same target would you then re-stack everything i.e. put the first nights lights,darks,flats,bias in group 1, second in group 2 and the new data in group 3 and then re-stack?

Yes, and save the file list after each time you add to a new group so you don't have to add everything from night one.

[The Lazy Astronomer]

28 minutes ago, Chefgage said:

So for example then for two nights of imaging you would use group 1 and group 2 tabs and then process as normal. If say a couple of weeks later you get another night on that same target would you then re-stack everything i.e. put the first nights lights,darks,flats,bias in group 1, second night in group 2 and the new data in group 3 and then re-stack?

Put the darks in the 'main group' tab - these will be applied to all lights in all other groups.

If you can share the flats between all the nights (ie. you left the camera on the scope), then the flats, associated flat darks and all the lights can also go in the main group tab.

If you have different flats for different nights, then put the lights with their associated flats and flat darks in their own groups. You can also stack the calibration frames separately and just add the masters into the relevant group(s) when stacking the lights if you wish. 

When adding new data, I would always restack all the lights from scratch (using prestacked master calibration frames, wherever possible).

[Chefgage]

12 hours ago, The Lazy Astronomer said:

Put the darks in the 'main group' tab - these will be applied to all lights in all other groups.

If you can share the flats between all the nights (ie. you left the camera on the scope), then the flats, associated flat darks and all the lights can also go in the main group tab.

If you have different flats for different nights, then put the lights with their associated flats and flat darks in their own groups. You can also stack the calibration frames separately and just add the masters into the relevant group(s) when stacking the lights if you wish. 

When adding new data, I would always restack all the lights from scratch (using prestacked master calibration frames, wherever possible).

Thanks, that sounds simple enough. Just need some more clear nights to add to the data

[The Lazy Astronomer]

1 hour ago, Chefgage said:

Just need some more clear nights to add to the data

Don't we all!! 😁

[Simon Pepper]

Hi all 

I have asked a similar question over on another forum and still not getting it. Let’s say you shoot over two months so two different sessions dust moats have obviously moved. How can you add data to the 1st stack? You surely need to run new stack new calibration etc so you are now left with two master lights how are those combined? I use PI. Thanks 

[Chefgage]

1 hour ago, Simon Pepper said:

Hi all 

I have asked a similar question over on another forum and still not getting it. Let’s say you shoot over two months so two different sessions dust moats have obviously moved. How can you add data to the 1st stack? You surely need to run new stack new calibration etc so you are now left with two master lights how are those combined? I use PI. Thanks 

From what I now understand. When you are adding new data you are re-stacking the old data with the new. So your first set of lights are calibrated with the calibration files you took originally. Then in the second group tab you put your new lights and new calibration files. DSS will then calibrate each set of lights with their corresponding calibration files. DSS then stacks all the lights from both groups together giving you one master light that you can then post process.

[Simon Pepper]

3 minutes ago, Chefgage said:

From what I now understand. When you are adding new data you are re-stacking the old data with the new. So your first set of lights are calibrated with the calibration files you took originally. Then in the second group tab you put your new lights and new calibration files. DSS will then calibrate each set of lights with their corresponding calibration files. DSS then stacks all the lights from both groups together giving you one master light that you can then post process.

Ok this makes sense and very interesting I didn’t know this existed so great Info. Next question which hopefully someone can answer how is that down in Pixinsight using the weighted pre batch processing? Thanks