Maxim calibration/align/stacking with data from multiple sessions

[LDUNN1]

I'm a new Maxim user having originally got it for the image capture side of the business, but I have just been trying out the Processing available within Maxim.

I have data of the same target, taken through the same filter (OIII) that was taken over multiple sessions, & as I setup & teardown after each session, I've taken Light FLats for that filter during each session. ie I have multiple session light data & corresponding multiple Flat Light data.

Is anyone else able to calibrate/align/stack data from multiple sessions with multiple Light flats, in one go? Or are you processing each indvidual sessions data separately & then combining?

What I've tried so far:-

In the 'Set Calibration' winodow I add groups just covering data through one of my narrowband filters - so I have 3 Light Flats taken on 3 different nights all through say the OIII filter. I also add separate groups for darks taken at each of the exposure durations I've used throughout the 3 nights (so lets say I have 3 separate groups of darks covering 600s, 1200s & 1800s), & finally I add a group for my bias shots. I've standardised on -10c for everything, so that removes some complexity.

Next, in the 'Stack' window I bring in my 3 sessions of OIII light data (each drops into its own sub-folder under the main group, then go to the 'Combine' tab & click on 'Go' - but I get a warning message pop up advising that I need to correct errors in the log window. The Log window appears & the error seems to be:

"Two Color group Group1 is missing required subgroups RG"

I've even tried changing the FITS headers to each of my data sets to try & help Maxim tie up the 'light' data with the correct 'Light Flat' data using the 'Filter' info in the FITS header. But even this has failed.

So is anyone out there able to get Maxim to calibrate/align/stack data taken through one filter but over multiple sessions each having their own unique Light Flats? Or is this beyond Maxim's abilities?

[daz]

It's beyond any software abilities I think....

You will need to calibrate and register each set of data on it's own, and then bring the stacked images together and align/stack those.

Darks are different because they can be scaled, but you can't do that with flats...

[LDUNN1]

Daz, much appreciate your response.........I think you are probably correct, it just looked like Maxim could probably handle it.

I was thinking that you can feed Maxim with separate multiple lights & matching flat lights for RGB & it copes with calibrating & stacking that, because it uses the filter name to match the lights with their matching light flat data (both being taken through the same filter, so I figured that if I specified a different filter name for each sessions lights & flats, then Maxim would use this to match the coresponding Light & light flat data together - even though they are all through the same filter on different sessions, the fact that I named the filters differently then Maxim would just get on & deal with it.......but everything I've tried on that front so far has failed ;-(

Out of interest, what stacking method would you use to stack the separate, but otherwise calibrated, data from the multiple sessions? Sum, Average, Median, Sigma Cap.?

[andrewluck]

Lawrence

You will need to stack the different sessions separately, matching the lights and flats for each session.

You're getting the missing groups error because you have loaded three groups of images for the one object and Maxim assumes they will be RGB groups. However, because you have the same filter used for all three groups they can't be combined in this way. If you right click the top level folder and select 'individual planes' then they would stack correctly.

Andrew

[RikM]

For multiple night stuff, I ran the calibrations first with each data set but didn't stack them, then I loaded the all calibrated files and stacked them. Only done it the once though so far.

In DSS you can add individual calibration files to each set of subs as separate groups. Just open a new tab and drop in the subs and flats into the group. Darks and bias go in group one with the first nights subs and flats. The common calibration frames are applied across all groups (nights)

[LDUNN1]

cheers Andrew & Rik for taking the time to reply to - really appreciate it.

I'm new to Maxim, and find myself somewhat surprised that it cannot handle data for the same object taken through one type of filter, over different sessions each with their own flats. It seems such an obvious thing that many would want to do.

I'll re-read your posts when I next have a play with my files.

[steppenwolf]

I know this is a really old thread but this issue has been bugging me recently as I wanted to change my work-flow to make it more automated and I came across this error message with some of my LRGB Data. The solution is simple but begs the question WHY?

When you use the stack command on several different filtered images which appear correctly in 'groups' pertaining to each filter type, Maxim allocates a colour to each filter group - or, rather it SHOULD. However, sometimes it doesn't allocate (apparently) so you have to allocate the colours manually. To do this, I just right-click on the group in the list box, select Select Group and choose the filter required.

This works perfectly.

 

[Davey-T]

It's very fussy about the stuff in the Fits file being identical, you can see if the info is different for the ones it doesn't recognise to ones that it does, also it sometimes doesn't recognise filters in images captured with Artemis Capture.

Dave

[steppenwolf]

46 minutes ago, Davey-T said:

It's very fussy about the stuff in the Fits file being identical, you can see if the info is different for the ones it doesn't recognise to ones that it does, also it sometimes doesn't recognise filters in images captured with Artemis Capture.

It can indeed be fussy but all the data was actually captured using MaxIm DL itself. Sometime, I may look into this further and see if CCD Commander is adding or subtracting something from the header as I am using that to control MaxIm.