I am not sure if this is the right place to start this topic but my friend has been experiencing some calibration problems recently. He has Asi294 mc cooled camera and shooting from Bortle 6 zone with Optolong L-Extreme and L-Pro. Recently he started having some reddish, pinkish type of circle at the center of images after stacking. We tried to figure out what was the problem so I wanted to his flats. You can see his flats down below that they don't look wrong. The problem is that what we see in those flats, they show themselves exactly in the stack image. Can someone tell what is the problem with this issue:
Edited by Ahilevs, 09 February 2022 - 05:15 AM.