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. Before I release it, I will make sure that everything is working properly and then I will release it.
It would be a large piece of programming to build a photometric calibration tool (like the one in The Astro Software That Dare Not Speak Its Name), but boy, would it be nice to have.
But this might be a way to implement it in APP without enormous investment.
Plate solving and photometric catalog lookup are long-since-solved problems. So for some set of stars in the image, we can know what color they're supposed to be without breaking new ground for software development. Adjusting the image so they match seems like a thornier problem.
But since we already have a mechanism for adjusting star color in the calibration tool, we can let the user do the hard part. What if instead of plotting a population of several hundred stars, we plotted a dozen -- twice? The catalog colors can be plotted in one dot color, and the image colors in another. Use the existing sliders to make the two populations coincide, bingo, calibrated. They don't have to exactly coincide, a "best fit" of the sort humans are good at (and computers, not so much) would likely be quite a good start for further tweaking, say in the HSL tool.
