Star Color Calibration ... very Magenta ๐Ÿ™‚  

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Main Sequence Star Customer
Joined:5 months  ago
Posts: 39
November 14, 2017 11:36  

Hi I am trying out the new Star Color Calibration but I am getting very strange results. Even if I only select the suggested star fields and not the nebula. Hiere is the background calibrated file:

(might take a while until it is uploaded):

https://www.dropbox.com/s/vhevvc2jd1gvwtf/combine-RGB-image-lpc-cbg.fits?dl=0


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Main Sequence Star Customer
Joined:5 months  ago
Posts: 39
November 14, 2017 14:55  

Just a screenshot to show the results: Same on my Mac as on my Windows 7 PC

Different boxes do not change the result. Tried calbrate background again, same. Same issue with my Crab Nebula image from yesterday. Might be the workflow -> Combine LRGB images combined with APP -> LP Removal -> CBG -> CSC -> Magenta. Never had that problem with my Canon.

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P.S. Yes there is a lot of coma, still trying to figure out the best working distance of my GPU to my ASIย  ๐Ÿ™‚ย 

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Thanks Mabula ๐Ÿ™‚

Edited: 5 days  ago

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Galaxy Admin
Joined:7 months  ago
Posts: 805
November 14, 2017 17:25  

Hi Frank,

Thank you for sharing this result.

I have downloaded your file.

I agree, the result is too purple no matter which stars you select. The multipliers reported in the Star Color Calibration module seem to overshoot to magenta.

R = 1.055

G = 0,88

B = 0,97

The RGB combine tool can be used to compensate, so I tried with the settings shown in the screenshot, just directly on your file:

So I use

R = 1,025

G= 0,96

B = 1.025

And mix some of the blue and red channels into the green channel.

I do think I know why this happens so I need to improve here, work on the module is not finished yet and I will use your image as well for further testing ๐Ÿ˜‰

Kind regards,

Mabula

Main developer of Astro Pixel Processor and owner of Aries Productions


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Main Sequence Star Customer
Joined:5 months  ago
Posts: 39
November 14, 2017 22:28  

Thanks Mabula, quite tricky to get this right. I imaging this is quite an algorithm ๐Ÿ™‚ Keep up the great work!


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Galaxy Admin
Joined:7 months  ago
Posts: 805
November 15, 2017 13:18  

Thank you Frank, yes, it's not simple to get it right for a large range of images. Currently the calibration is done on only 3 parameters. That keeps it simple, but also very limited. I am working to calibrate the colors with 9 parameters (and possible even corrections for both atmospheric and galactic extinction).

So to be continued..., I'll use your image for testing as well, so thank you ๐Ÿ˜‰

Mabula

ย 

Main developer of Astro Pixel Processor and owner of Aries Productions


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Main Sequence Star Customer
Joined:5 months  ago
Posts: 39
November 15, 2017 15:04  

Great, looking forward to it. In case you need the stacked and registered LRGB data I used for the combine, please find the dropbox link below:

https://www.dropbox.com/s/83tzhq5tjuv4h3l/Archiv.zip?dl=0

In the combine tool I used the defaults of LRGB 100% each.


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Galaxy Admin
Joined:7 months  ago
Posts: 805
November 16, 2017 16:18  

Thanks Frank, I downloaded the data ๐Ÿ˜‰

Mabula

Main developer of Astro Pixel Processor and owner of Aries Productions


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