I use DSLRs and take lights, darks, flats, and flat darks (not bias frames, although bias frames and dark flats are indistinguishable when the exposure time is something like 1/200 second, as mine are).
The BatchPreprocessing script seems to work fine when I put in the flat darks as bias frames. I see from the log that the flats are calibrated with the regular darks (the darks that match my lights), which are scaled down by your noise analysis algorithm.
But I think I get even better results if I put some of my flat darks in as darks (and the rest as bias). Because of the exposure time, they become a separate group of darks from the regular darks, and they are used to calibrate the flats.
BatchPreprocessing won't let me put the same files in more than one category. However, I'm thinking of hacking it to add a checkbox, "Bias frames are flat darks," which would tell it to dark-subtract the flats using the master bias rather than the master dark.
A couple of questions about this...
(1) Am I on the right track here? Should it work better that way?
(2) If I make the modified version of BatchPreprocessing, will I be free to distribute it? Of course I can use anything for my own purposes, but I'm in the process of revising Digital SLR Astrophotography and want to give my readers a quick introduction to PixInsight, of which this might be part.
If nothing else, I want to give good advice about how to use BatchPreprocessing in this situation.
Thanks in advance to those who are about to give helpful responses!
