I recently upgraded my setup to monochrome and have found a weird dark ring found in my master light and flats. My equipment is an ASI533MM Pro, Redcat 51, Antlia 4.5nm Edge Ha 1.25" filter screwed in like this: https://www.cloudyni...-1613438879.jpg . I took 5 * 5 minute guided exposures using the ASIAir. I then took 20 flats and 20 dark flats and didn't take dark frames because I didn't think it was necessary for the camera.
In the individual stretched light frames, this pattern doesn't seem to exist. I would like to know what has happened here so that I can decide whether to return some of my equipment (within the 30 day period). I have attached some pictures to show what it looks like. I stacked in DeepSkyStacker and did just an autostretch in Siril for each of the images and then took a low res copy and posted them here.
Edited by TamsyMan, 12 February 2024 - 03:37 AM.