PixInsight Super-Neewbie and DBE - Forums

Topic starter

Apr 3, 2022

Hi All,

I downloaded my trial version of PixInsight yesterday and have a question on DBE. I was expecting to see a washed out background consistent with light pollution for a stacked image of M42 (210 lights @ 30 sec), but instead when I use the STF function on the background image I see a rainbow of colors (see attached image). My setup is a SpaceCat51 with ASI183MC Pro OSC and using the L-enhance filter. Any thoughts? Is this to be expected?

Thanks and climbing the learning the curve.

Jim

Well Written Respectful

Linwood Ferguson

Apr 3, 2022

Hit the button at the top with a "24" on it, and it will smooth out – the rings are an artifact of low resolution rendering.

As to colors, if it's a color image it will remove a color background. Remember that the background is being stretched hard to make it visible to your eyes, that does not mean that in the original it looked that extreme. The background is useful for seeing what it did, but you have to look at the modified original to see the real impact. If you didn't get one, look at the bottom and be sure to set the correction type to subtract (or in rare cases division).

Helpful

Jenafan

Apr 3, 2022

Hi Jim, you have to switch on the 24bit LUT to display the bg model without artefacts.
Greetings,
Jürgen

Aastro123

Apr 3, 2022

Hey Jim!

Looks about normal. At the top and bottom left there is a dark area in the stretched DBE… This may be due to one of the points set for the background being placed on a bright object such as a star. If the new image looks good, I wouldnt worry about it. If there is weird darkening around a star, then what I explained^ happened.

I usually use the manual DBE (Not the ABE) and set my own points in the background at a size of say 30 (under sample generation and default sample radius). Tolerance of 6.0 and shadows relax of 2.0 (under model parameters). Ill do a division correction and then a subtraction if needed.

Again, if youre happy with the DBE, you probably did it correctly

Andy

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pfile

Apr 3, 2022

btw you say DBE in the question but the background model seems to have come from ABE. not that this affects the answers given, the 24bit LUT is sometimes necessary for the background models in both processes at times.

AstroCapture325

Topic starter

Apr 3, 2022

Thanks everyone, these responses are very helpful and worked just as you suggested.

@pfile: You are correct, even though I used the term "DBE" in the thread, the attached image is from "ABE" .

I've viewed several YouTube videos, but does the group have any suggestions for PixInsight beginner tutorials that would provide a solid foundation for me to build upon?

Jim

Linwood Ferguson

Apr 3, 2022

If you want video, Adam Block's Fundamentals is very good. Lots of detail, but very thorough and authoritative. Not free though, if you are looking for youtube (though he did put some there ,search by his name).

Aastro123

Apr 3, 2022 · Edited: Apr 3, 2022

@apo20232

Visibledark on youtube 100% made pixinsight seem not so scary