Author Topic: artifacts introduced around bright stars during integration  (Read 632 times)

Offline storyface

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Hello gurus,

Hoping someone recognizes this pathology; see attachment.

Bright stars look like they are wearing ugly wigs :(

I am stacking using the BatchPreprocessing script and winsorized sigma clipping. When I bump up the sigma high parameter to 6, the effect is reduced, but not eliminated, and I also start to notice airplane trails making it into the final image, so that's not much of a solution.

This is zoomed way in on a stacked xsif of 23 or so 10-minute exposures plus flats/bias. No darks. Other details: Canon 6D, raw (cr2), iso1600, TV-NP101, Lumicon LPR.

Offline ngc1535

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Re: artifacts introduced around bright stars during integration
« Reply #1 on: 2018 January 27 19:13:12 »
Hmmm... those pixels look pretty grainy (blocky) for a stack of 23 images using rejection.
You didn't mention your alignment method. Misaligned images will certainly look like this- especially if using nearest neighbor.
Just throwing out a first stab.
-adam

Offline storyface

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Re: artifacts introduced around bright stars during integration
« Reply #2 on: 2018 January 27 19:32:34 »
This is a zoom greater than 1:1 to show the problem, so that explains the blockiness, or do I misunderstand you?

Offline msmythers

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Re: artifacts introduced around bright stars during integration
« Reply #3 on: 2018 January 27 19:42:41 »
You might want to look at this posting. I think it might have your answer.

https://pixinsight.com/forum/index.php?topic=11986.msg


Mike

Offline storyface

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Re: artifacts introduced around bright stars during integration
« Reply #4 on: 2018 January 27 22:16:26 »
@Mike, thank you for the link. That sounds like my problem. But if the cause is weak signal, does that fit with ISO1600 for 600 seconds through a light pollution filter? I would have thought I'd be safely in high signal territory.