I'm slowly getting experience with astrophotography, but every night I run into something I can't explain.
Friday night I gave up on the scope/imaging software I was using (temporarily, anyway) and started using KStars & Ekos. This software looks more complicated, but it "just worked" when I tried getting all my components working with it and "just worked" when I tried it tonight for actual observing (the first clear night in weeks). I decided to capture some good images of Andromeda (because it's bright, easy for a beginner). I knew it wouldn't fit in my FoV, but still thought I'd get great images -- this was the first time I successfully auto-guided. The problem is I ended up with 10 x 300s exposures that show stars "oddly" like there's a halo on one side. I don't seem to see this in other photos I've taken, so it was either specific to KStars/Ekos or the auto-guiding of the mount. Or could it be dithering?
Celestron Edge HD 9.25 on CGX
.7x Focal Reducer
KStars and Ekos controlling the mount, focuser, guide cam ASI174MM and main cam ASI294MC-Pro.
The main cam was set to abort exposures if guiding deviated by > 4". The default is 2, but even though my guiding is generally under 1" it would spike often enough to abort most of the 5 minute subs.
See attached image. Note that because CloudyNights won't let me upload a FITS image, or any image over 500KB (how 1986 is that?), I had to screen shot just two stars south of the M31 Core, near the center of the field. They look the same in the screen shot as they do in the source image, so don't assume it's lossy JPEG compression or artifacting. It appears on all the stars across the field. Any ideas?
Edited by MountainAir, 16 December 2019 - 03:40 AM.