Greenish background when imaging the Needle Galaxy

Discussion of using SharpCap for Deep Sky Imaging
Moonstruck
Posts: 112
Joined: Tue Aug 17, 2021 4:34 pm

Re: Greenish background when imaging the Needle Galaxy

#21

Post by Moonstruck »

Thanks everyone for the detailed replies! I have just started using Startools, and this is very helpful. I am currently searching for a good Startools tutorial (short video maybe?) that will show me the basics of this program.

Brian, I captured the flats the morning after I took the lights, at daybreak (maybe a few hours later?). I don't use a filter wheel. I didn't remove the camera, or change anything except the exposure for the flats, and added the white T-shirt to the end of the telescope when I took them (they were sky flats). I changed the exposure so that the white curve was at 50% on the histogram.

I am going to go through these replies in detail, as there is a lot of information here. Thanks again everyone, I really appreciate your help!
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turfpit
Posts: 1779
Joined: Mon Feb 13, 2017 8:13 pm
Location: UK
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Re: Greenish background when imaging the Needle Galaxy

#22

Post by turfpit »

John

See viewtopic.php?t=5417.

You now have a couple of things to investigate:

flats, redo or luminescent panel or use ... h a tablet
  • dithering
There is a lot in the posts above for you to digest - it will take time and many re-reads. When I am trying to solve a problem, I only change one thing and then test - hard lessons learned from 25 years in the computing industry.

Good luck.

Dave
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