Trouble with DBE

bmimiaga

Well-known member
I just bought a new ASI1600MM camera and imaged M81 in LRGB on it's first run. After integrating the LUM image I attempted to use DBE to even out the background noise and was not able to accomplish it. It seems like the DBE processed image result generated vertical bars of shadows no matter what settings I changed. Does anyone have an idea of what I'm doing wrong? Here's an image of the integrated image and DBE processed image. BTW, my Red, Green and Blue integrated images process well with DBE. Thanks for your help! Bob
 

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It may be my imagination, but I think the bands are already there in the original Lum image; DBE has just removed a lot of gradient background and made them clearer. I've never seen anything like this in my limited experience with astrophotography, but it does look rather like a diffraction pattern (I'm ruling out patterns induced by the sensor, since they would be there in the other filter images). I can imagine various ways to produce this, but I would expect any phenomenon like this to be known to more experienced astrophotographers (rather like the "Newton's rings" that sometimes plague solar astrophotography).
 
It may be my imagination, but I think the bands are already there in the original Lum image; DBE has just removed a lot of gradient background and made them clearer. I've never seen anything like this in my limited experience with astrophotography, but it does look rather like a diffraction pattern (I'm ruling out patterns induced by the sensor, since they would be there in the other filter images). I can imagine various ways to produce this, but I would expect any phenomenon like this to be known to more experienced astrophotographers (rather like the "Newton's rings" that sometimes plague solar astrophotography).

Fredvanner, you're right. I brought the integrated LUM image into PI and boosted the STF autostretch and sure enough I could see the lines. The only explanation I can come up with is my light box used to create my Flats or the way NINA creates Flats. I'll have to investigate further.
Thanks for your ideas.
Bob
 
Have you looked really closely at the raw subs? (The light box is an easy target, but I'm not convinced).
 
So I looked at my LUM flat images and there is horizontal lines on them when I boost the STF. Not so with the other RGB raw flats. Any ideas? Thanks for any input.
Bob
 

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That looks the other way round! Is one of the images rotated? Could you upload a few raw subs (a couple of L; a couple of one filter, say G; a couple of flat) and post a link. This does look wierd!
 
No the original images I posted were geometry rotated 90 degrees in PI for aesthetics.

I just tried using another set of Flats I created the day before with my OSC camera. They don't have the shadows and when I integrated the LUM images with these older flats they seemed to work. I know I'm crossing color and mono flats but I'm just trying to troubleshoot the problem. So the problem seems to be with my new mono LUM raw flats somehow containing these shadows....
 
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