Not really big into astro photography but it is fun and enjoy doing it. I use a Pentax K50 with a 200 mm lens and have done maybe a dozen different shoots with no issue. But last week, while shooting M31 had a problem I can’t figure out.
I shot a bit over 600 2.5 second exposures and 15 dark images. Then shot my flats and biases. When I tried to stack using the normal osc script I got about 30% negative pixels and the program wouldn’t stack the images.
I then used some other scripts. Tried without the darks, only flats and bias. Same result. I then tried with only the darks, same result. Logically it would seem something was wrong with my lights. I then stacked the images without using any calibration files and actually got a pretty good final image considering the equipment.
Since I got a good stacked image without calibration files I assume the light images are good. The next day I redid the calibration images after reviewing the procedure to make sure I wasn’t mixing the darks and biases. The camera temperature was close to the same so the darks should be OK. Same results, negative pixels???
Any ideas on what is happening? Any ideas will be appreciated.