Patchy light pollut...
 
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Patchy light pollution removal?  

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(@chrisboar)
White Dwarf Customer
Joined: 2 years ago
Posts: 13
January 17, 2021 20:26  

Having issues removing some bad light pollution, or at least that's what i think it is.

Ending up with patchy results which just move around when I try and remove it with repeated attempts. 

Any suggestions? 

This is one example :-

50mm Orion Widefield Pre LP

The FITS file is here is in a compressed ZIP file if anyone would like a stab at it. 

Thanks for any help.

Orion Widefield FITS file

This topic was modified 2 months ago 2 times by ChrisBoar

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(@wvreeven)
Galaxy Admin
Joined: 2 years ago
Posts: 593
January 17, 2021 21:33  

@chrisboar That doesn't look like light pollution to me because that usually isn't as patchy as in your picture. Is this an integration of a single FOV or a mosaic? What calibration files did you use? Is this with a DSLR camera? What else can you tell us about how the image was created?


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(@chrisboar)
White Dwarf Customer
Joined: 2 years ago
Posts: 13
January 18, 2021 00:10  

@wvreeven

Well it's patchy after my attempt at removing the LP. I'm wondering if this is very thin cloud? Transparency was forecast as below average.

This is an integration of a single FOV, calibrated with the usual master calibration frames; Dark/Flat/BIAS/BPM. I shoot with a Nikon D5500 H-A modified camera with a IDAS LPS-D1 Light Pollution Filter .

I've included the pre-LP FIT's file link below in a compressed file if that helps. Thanks!

Orion unprocessed FITs

 

 

 


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(@vincent-mod)
Universe Admin
Joined: 4 years ago
Posts: 3075
January 18, 2021 17:32  

Thanks Chris for that file, I'm also taking a look.

I have to say that the light pollution is very, very strong in it. This can cause a lot of things like internal reflection and what not. Exactly why it looks spotty is hard to say, but I'd bet that internal reflections might contribute to it. This is making it extremely difficult to correct properly as these are not regular light pollution gradients. The only way to make this better is to get a solution for the light shining onto the telescope.

This is the best I could get it to, with not stretching too much and some added contrast, you can at least get it somewhat ok. 🙂

Orion 50mm mod St

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(@chrisboar)
White Dwarf Customer
Joined: 2 years ago
Posts: 13
January 18, 2021 23:36  

Thanks Vincent. Yep I think you're right. I was lazy and set up too close to my light polluting house, lol....lesson learned.

 

 


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(@vincent-mod)
Universe Admin
Joined: 4 years ago
Posts: 3075
January 19, 2021 12:52  

No worries, always nice to see what the issue is so it can be fixed and you can enjoy some great pictures again. Because I see enough signal even in the polluted data. 🙂

 


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