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PixInsight => General => Topic started by: timc770 on 2015 April 15 18:33:47

Title: Newbie Question - Stacking only DSLR light frames?
Post by: timc770 on 2015 April 15 18:33:47
Hi,

I've got a few dslr light frames that I wanted to use to play around in pixinsight (I did the in camera dark frame subtraction).  I have no flats, bias frames, etc.  This isn't a serious image... just want to practice.  I can't seem to get the batch preprocessing script to work with just the 3 light frames.  I get an error that says "Cannot execute instance in the global context. Reason: No master calibration frames or overscan regions have been specified."

Can I use this script with only the 3 light frames?

Tim
Title: Re: Newbie Question - Stacking only DSLR light frames?
Post by: james7 on 2015 April 16 15:26:54
If you want to use the BatchPreprocessing script you need at least bias and dark frames. In fact, the main reason for the existance of the BatchPreprocessing script is to do image calibration, so unless you have bias, dark, and flat frames there isn't too much point to using the script.

So, you'll have to do a manual debayer operation (BatchDeBayer script), followed by StarAlignment (under ImageRegistration), and then ImageIntegration. For a quick practice run with three files you can probably just use the defaults for each process and it should take only a few minutes to perform the entire set of operations.
Title: Re: Newbie Question - Stacking only DSLR light frames?
Post by: timc770 on 2015 April 16 17:46:18
ok, that makes sense.  Thank you very much for the response James.  I wound up stacking them in DSS so I could play with the processing in PI.  I'll normally have bias and flat frames as well.
Title: Re: Newbie Question - Stacking only DSLR light frames?
Post by: CRWPhoto on 2015 June 08 18:56:40
If you want to use the BatchPreprocessing script you need at least bias and dark frames. In fact, the main reason for the existance of the BatchPreprocessing script is to do image calibration, so unless you have bias, dark, and flat frames there isn't too much point to using the script.

So, you'll have to do a manual debayer operation (BatchDeBayer script), followed by StarAlignment (under ImageRegistration), and then ImageIntegration. For a quick practice run with three files you can probably just use the defaults for each process and it should take only a few minutes to perform the entire set of operations.

Great information!  I was having the same issue as the OP and gave this a try.  Worked like a charm.  Thanks!
Title: Re: Newbie Question - Stacking only DSLR light frames?
Post by: sschahal on 2016 October 02 12:23:57
James:

re: So, you'll have to do a manual debayer operation (BatchDeBayer script), followed by StarAlignment (under ImageRegistration), and then ImageIntegration. For a quick practice run with three files you can probably just use the defaults for each process and it should take only a few minutes to perform the entire set of operations.

The above sequence at least works for me although the end result is quite noisy.  But when I try to use the Batch pre-processing script I get the RANSAC error message saying registration failed as it could not align the images.

Appreciate any help.

Thanks