Author Topic: Artifacts during Alignment/Stacking  (Read 906 times)

Offline Dimitris Platis

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Artifacts during Alignment/Stacking
« on: 2017 March 27 00:07:23 »
I am experience an artifact during the alignment/stacking process with Pix.
The problem is some sort of black pixels around stars and a rather ruggedly appearance of the stars.
To solve this I have aligned/stack uncalibrated FITS and I have tried changing various parameters on the Star Alignment module as well as in the Image Integration module, ...alas the problem remains.
I have uploaded a link that contains all the FITS.......in the hope that someone finds a combination that works (http://www.mediafire.com/file/m5t098yyz2966a3/Red.rar).
I have also uploaded an image that shows the problems (image on the right) and the corresponding image on the left from DSS that doesnt have this problem and shows nice round stars (the same fits were loaded in both cases).

Thanks
Dimitris

Offline msmythers

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Re: Artifacts during Alignment/Stacking
« Reply #1 on: 2017 March 27 01:12:54 »
Dimitris

I think the hot pixels are giving the auto pixel interpolation a challenge. I changed the interpolation to Bicubic B-Spline and the edges cleaned up. The down side is this is an aggressive interpolation scheme. Here is a comparison of the reference image 0007, the registered image 0013 and the final integrated image.

I don't know if you have a set of calibration files for this image but I would hope with those this would not be a problem.


Mike
 

Offline Dimitris Platis

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Re: Artifacts during Alignment/Stacking
« Reply #2 on: 2017 March 27 01:26:44 »
Thanks Mike,
I will have a set of fresh calibration frames.....but it wont changed anything I guess (already tried 6 month old ones).
Its the alignment algorithm...