UPDATE FROM MABULA
I have had a very rough 2 months unfortunately health wise. I was struck 3x in a row with bacterial infections. The second infection occurred  after a routine hospital checkup and I became very sick. I had to rest and take a lot of antibiotics. Once I was recovering and restarting work 1 month ago, I again became sick. The infection was not yet gone, so even more antibiotics and rest was needed. Needless to say, it took a lot of my energy and I needed a lot of rest.
Finally, the infection is really gone and my energy is coming back step-by-step now and I have started work again. I am terribly sorry to have kept you waiting for support. I will address all outstanding questions and e-mails step-by step and will be on the forum daily from today.
APP 2.0.0-beta47 will come soon as well, a lot of work was already completed before I became very ill, so the release is also nearly ready for you. Beta47 will be much faster actually. Many workflows will be more than 2x faster, mosaics can even be 10x faster than before because registration really received a major boost... all compared to beta46. Â Before I release it, I will make sure that everything is working properly and then I will release it.
After having problems getting other programs to recognize my master flats, I realized that, instead of the standard key word "FILTER" (which is used in the lights), the MF files contains "FILT-1" and then "FILTNUM." I presume if there were two filters used for the flat, there'd be FILTNUM = 2 and a FILT-2 etc.
I think I understand the reasoning, but that seems to me an edge use case. Meanwhile, only APP recognizes what FILT-1 means, and no other program I tried seems to. Could we name the first filter FILTER like everyone else does, and maybe use FLT-2 etc for the exceedingly rare case that someone uses multiple filters for one flat, if that's needed at all?
I just ran into this and it is a significant problem for me. i just processed two weeks worth of flats at multiple rotator angles, only to find I cannot use them b/c the filter keyword is wrong. I used multi-session to stack them by date and rotator angle, and kept the same dark files. I did this b/c Pixinsight is way too slow to deal with for stacking all these files and the file sizes are insane, not to mention its slow.Â
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However now I am stuck since apparently all of my master flats I just generated are no good.Â
@mikecmp I hear you. For now: Download ASTAP (free) and that lets you easily batch change fits header keywords. It's a workaround, though takes extra steps (and yet another program).
APP allows you to do that too (In Tools), but that does create a new file each time.
