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PI Star Alignment fails on Drizzled images

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#1 ssa2294

ssa2294

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Posted 28 November 2021 - 07:37 PM

I have several image sets of varying quality that I have no problems doing StarAlignment. The same images are run through DrizzleIntegration and then fail. Alignment is off the L master, and fails for R, G, B, HA, O3, & S2. 

 

I have another 4x panel of IC 1831 where it is just 2 panels (Panel 3 & 4) where only the S2 fails alignment but this fails in Mosiac working mode. I can however combine the 2x panel's S2 for originals, just not the drizzled. Thus a 4 panel mosiac can not get completed. For the S2 images the stars are not the best, brighter stars look good whereas really faint stars are streaking from the 9 minutes subs. 

 

I have played around with settings some, but nothing works and now I am out of ideas and options and hope to get some advice or solution to move forward. The poor quality sets I am not too concerned about, my focus was very poor at time and I will eventually redo these. But the 4 panel mosaic failing on S2 image set is extremely frustrating as I am so close to stitching the final image. Panels 1 & 2 already processed, combined, aligned, etc.. just fine. 



#2 pfile

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Posted 28 November 2021 - 11:39 PM

the way you are doing this is kind of old fashioned... most people use MosaicByCoordinates + GradientsMergeMosaic or PhotometricMosaic. but anyway since you are using SA, are you creating previews over the overlap areas of the different panes? this can help guide StarAlignment in mosaic mode.

 

rob



#3 ssa2294

ssa2294

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Posted 29 November 2021 - 08:36 AM

I can look deeper into other methods of doing mosiacs, but the problem at hand is really about Staralignment failing on drizzled images. The same sets of R,G,B,HA,O3, & S2 all align natively, but their drizzled counterpart fails. 



#4 pfile

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Posted 29 November 2021 - 07:08 PM

well, are you using previews to restrict the FOV for matching? sometimes this is necessary. it might not be because of drizzle but because of the image size, etc.

 

rob



#5 ssa2294

ssa2294

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Posted 30 November 2021 - 12:37 PM

well, are you using previews to restrict the FOV for matching? sometimes this is necessary. it might not be because of drizzle but because of the image size, etc.

 

rob

Thanks for the tip, and answer would be nope. But this gives me a good step in what to learn next.

 

BTW, I can not explain it, but one of the image sets that was failing repeatedly now aligned. I was bored at work and decided to try Staralignment again just to see if I could get more detailed log output, and of course it worked then. 




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