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.
Seems to be some debate about whether gain for flats needs to match gain for lights - in my view not, although APP flags a warning about this. Fair enough to point that out or any other potential issues. Trouble is it doesn't seem to flag it at the outset - it waits a while which is a pain if you hit the integrate button to do the whole process and come back hours later to find it's interrupted with a warning.
Summary - could all warnings be made at the outset, rather than part way though processing?
Thanks Tom C
Flats need a proper illumination of your sensor, through the optics of your setup to be able to correct for vignetting (and dust). These are characteristics of the setup and that data isn't something that needs to match regular astro-images and calibration data. You can set the gain to 0 (for max dynamic range) and take 1-2 second exposures that will have the linear histogram land at about 60-70% (the only thing is that you shouldn't clip the data to the right, the 50% you see quoted a lot isn't important). The flats do need their own calibration data, dark-flats and these do need to be at the same gain etc. as the flats.
Could you post a screenshot of the warning as I can't remember it does that, in my view it shouldn't be about having that match with the lights...
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To add to what Vincent wrote: the gain of the flats does not have to match the gain of the lights. Neither do offset, temperature and exposure time. However, the flats do need to get calibrated and for that either bias and darks or dark flats with the same gain, offset and temperature are needed. In case of dark flats, the exposure time needs to match as well with the one of the flats.
Thanks guys. We are all on the same page with regard to flats then - important thing is to make sure that the settings for the flats match the setting for the dark flats. And also as you say to ensure working on the linear part of the sensor.... which is something I've only just realised after 4 years of problematic flats!! It seems that setting the average ADU of the flats to match the average ADU of the lights may be the surest method. (For my ASI1600 cool at least)
Re the APP error message, which was the main point of my post - I did one re-run and it seemed fine so maybe I just did something wrong. If I get the same issue again I'll post back.
Thanks for the feedback - what a great forum!
Kind regards
Tom
Thanks so much for appreciating the help! 🙂
Yes, looking at the ADU is a good way to check if you're aiming for a good value. Glad it helped and I hope the processing is going better now?
