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Checkerboard pattern after stacking and star removal?

Russell Croman Astrophotography StarXTerminator Luc Coiffier DeepSkyStacker (DSS) Processing Deep Sky Artifacts
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Danny Lee avatar
Danny Lee avatar
Hi all, 

This morning I stacked together some WIP data collected so far just to see how it's looking. 

No processing other than:
- 45x300sec stacked with darks only (no flats, dark flats) Stacking with WBPP and in DSS produces the same result
- Dynamic crop to remove stacking artifacts 
- Stretched using an unlinked STF stretch
- Stars removed using StarXterminator

Has anyone seen this before, any ideas what could be causing this pattern? I also tried gradient removal techniques before removing stars but that still resulted in this pattern.


Thanks
Danny
Danny Lee avatar
Danny Lee avatar
Apologies, perhaps I was a bit premature posting here but I think I've solved it. 

It was caused by StarXterminator, ticking the 'large overlap' box before running star removal fixed the issue. 

Happy to delete this post or leave it here in case anyone else has the same problem down the line?
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Richard avatar
Richard avatar
My understanding is that StarXterminator breaks your image down into separate tiles and analyses/extracts stars based on this. So if there was an error in this process (like ticking the overlapping box) then that would explain why you saw a checkerboard pattern on your image.
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AstroBillUK avatar
AstroBillUK avatar
Large Overlap option can help but doesn't necessarily complete eliminate the grid. Not sure what has changed. I never used to get this.
Azhar Rana avatar
Azhar Rana avatar
Thanks for this post, Danny. I'm getting this as well, but even with out ticking 'Large Overlap' I'm still getting the pattern. Can't see it at all before StarX. Anyone have any another suggestions?
Göran Nilsson avatar
Göran Nilsson avatar
I just had the problem and ticking the large overlap box solved it, so thank a lot for that info! The odd thing is that it happens very rarely. I think I saw it once before with an older version of StarXT, but by now I have used the new version on at least 100 images and then it happened on the 101st and I have no idea what in that image triggered it. As said in this thread I also read somewhere that it has to do with StarXT dividing the image up in squares when doing its job.
Cheers, Göran
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