Strange artifacts
Posted: Tue Sep 29, 2020 1:00 am
Hello, I have my first question about an issue I could not resolve on my own. I have processed just over a dozen or so images since starting this hobby last year and this was a first for me.
I'll cut to the chase, here is the issue, I have a weird color "vignetting" in my stack that I have never seen before and was difficult to remove. This is a screen shot of the completed Wipe just before hittin Keep
Here is the Cocoon from a month earlier, same point wiped ready to hit keep. I show you the Cocoon, since this has been typical for ALL my imaging prior the the Iris. I've always breezed through wipe without issues. I did in the Cocoon too, but Iris was a killer. Both of these were shot in the same manner, same equipment, substantially similar location in the sky, I really didn't expect any issues. I started the Iris session at an Altitude of 62° and ended the night 6 hours later at 37°. I am at a longitude of 40°. Booth sessions had new Dark, flat and Bias frames, with the only difference that The Iris was shot at ISO 100 instead of ISO 200. Thinking I had a calibration issue, I went through and replaced all my cal frames on set at a time, but it was in the subs. I even stacked a half hour of subs w/o cal frames at the start and middle of the session just to see, and it's in there. Could this be the California forest fire smoke?? I tried for a night when it was forecast at a min. Or is there something different about this object that I need to process uniquely. I tried masking off just the center and it really didn't seem to help me much. In the end I am fairly happy with my result, but I feel I sacrificed some signal when minimizing the LP in Wipe?
I'll cut to the chase, here is the issue, I have a weird color "vignetting" in my stack that I have never seen before and was difficult to remove. This is a screen shot of the completed Wipe just before hittin Keep
Here is the Cocoon from a month earlier, same point wiped ready to hit keep. I show you the Cocoon, since this has been typical for ALL my imaging prior the the Iris. I've always breezed through wipe without issues. I did in the Cocoon too, but Iris was a killer. Both of these were shot in the same manner, same equipment, substantially similar location in the sky, I really didn't expect any issues. I started the Iris session at an Altitude of 62° and ended the night 6 hours later at 37°. I am at a longitude of 40°. Booth sessions had new Dark, flat and Bias frames, with the only difference that The Iris was shot at ISO 100 instead of ISO 200. Thinking I had a calibration issue, I went through and replaced all my cal frames on set at a time, but it was in the subs. I even stacked a half hour of subs w/o cal frames at the start and middle of the session just to see, and it's in there. Could this be the California forest fire smoke?? I tried for a night when it was forecast at a min. Or is there something different about this object that I need to process uniquely. I tried masking off just the center and it really didn't seem to help me much. In the end I am fairly happy with my result, but I feel I sacrificed some signal when minimizing the LP in Wipe?