Fixing blue star bl...
 
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Fixing blue star bloat  

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(@bokemon)
Brown Dwarf Customer
Joined: 2 months ago
Posts: 9
November 29, 2020 22:52  

Hello

I have what is a common problem with many refractors: the red and green channels can be focused sharply, but some of the stars under the blue channel are significantly larger.  I think what is happening is that even within the blue filter passband there is still significant dispersion, i.e. the color blue-green focuses ok, but the color blue-violet becomes out of focus.  When viewing the blue image UNSTRETCHED, most of the stars are ok, and maybe only a little wider, but when viewing STRETCHED there is a significant blooming of some of the brighter stars.  So then when I combine the images, the stars have a blue ring around them.

Anyway, is there a way to fix this in the program?  I tried the checkbox of align stars, but that didn't help.


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(@wvreeven)
Black Hole Admin
Joined: 2 years ago
Posts: 484
November 29, 2020 23:03  

@bokemon At the moment there is no way to reduce star halos in APP.


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(@vincent-mod)
Universe Admin
Joined: 4 years ago
Posts: 2909
November 30, 2020 12:48  

No indeed, halos are tricky. The light pollution correction may work a bit for very large halo's, but I think only when it's more of a gradient coming from just outside the frame for example.


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(@bokemon)
Brown Dwarf Customer
Joined: 2 months ago
Posts: 9
November 30, 2020 21:26  

I'm not talking about giant halos - it's just a few pixels worth.


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(@vincent-mod)
Universe Admin
Joined: 4 years ago
Posts: 2909
November 30, 2020 21:34  

Yes, so my example was for these more giant ones. There it would still work, for smaller ones there is no real solution yet.


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