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Anyone Know What's Going On with this Image?

Acquisition Gradient Removal Processing Deep Sky
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Jerry Gerber avatar
Jerry Gerber avatar
This stretched integration (without any post-processing) was taken over 3 nights.  There were clouds passing through and the moon was about 70-85% full. 

Anyone know what these gradients are?  The were not on the original subs. at least not when using Screen Transfer Function to view them,  so either it's my flats or something in processing. I was able to remove them in post-processing, but I want to know what they're caused by.





Here's the version I came up with from these subs:
https://www.astrobin.com/cigrit/
Wim van Berlo avatar
Wim van Berlo avatar
Could it be molecular clouds or ifn? Compare to this image

https://astrob.in/boku69/0/

cs,

Wim
andrea tasselli avatar
andrea tasselli avatar
That's galactic cirrus and you shouldn't zap it.
Jerry Gerber avatar
Jerry Gerber avatar
andrea tasselli:
That's galactic cirrus and you shouldn't zap it.

Interesting.  If I knew they'd been there I'd increase my exposure time to 12 hours.  It's not too late.

I re-processed it and left the galactic cirrus in.  Thanks for pointing that out to me.
Tony Gondola avatar
Tony Gondola avatar
You have to be careful with background extraction because as you've seen in your case, it can and will, at times, try to remove real data.
Well Written
Jerry Gerber avatar
Jerry Gerber avatar
You have to be careful with background extraction because as you've seen in your case, it can and will, at times, try to remove real data.

Lesson learned!  Although the Background Extraction was not the culprit here.  The culprit was me, thinking it was a gradient.  I removed it by hand in post-processing.   Now it looks better: