As part of Veil Nebula October 29 2022, noticed an issue with my dark frames. I thought I must have some light leaking in somewhere. I decided to retake dark frames, and still saw the same thing. Then I noticed the same pattern in my light frames.
After some digging around, I found out that what I was seeing was “amp glow”. On my camera it probably isn’t actually an “amp,” but some of the electronics emitting heat and/or infrared light which is being picked up.
At least I know I’m not making this up. Using the calibration frames did get rid of this artifact, but I was certainly confused!
More information:
Dark Frame Issue with an ASI294MC Pro - CloudyNights