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Strange trails or (bad?) pixels

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(@infoarnaldolopez-nl)
White Dwarf
Joined: 4 years ago
Posts: 14
Topic starter  

Hi,

 

I just tried to stack some long exposure (30 to 90 sec.) of comet Neowise and got strange pixel trails in an opposite direction of the startrails. Would this be solved if I had made darks and bias etc.? 

 

Thanks,

Arnaldo

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This topic was modified 4 years ago by Arnaldo Lopez

   
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(@vincent-mod)
Universe Admin
Joined: 7 years ago
Posts: 5707
 

Very likely yes, these can be bad pixels.


   
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(@infoarnaldolopez-nl)
White Dwarf
Joined: 4 years ago
Posts: 14
Topic starter  

@vincent-mod Thanks for your reply... Is there any way to minimize them without darks etc.? 


   
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(@vincent-mod)
Universe Admin
Joined: 7 years ago
Posts: 5707
 

You can try to use cosmetic correction in tab 2, switch the options on for hot pixels, I'm not entirely sure if that works without any calibration data (never tried that). Brin the hot pixel kappa down to maybe 2.5 or lower to make it more aggressive.


   
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(@infoarnaldolopez-nl)
White Dwarf
Joined: 4 years ago
Posts: 14
Topic starter  

@vincent-mod Thanks! I’ll just give it a try... And maybe I’ll make some darks too... If they are bad pixels, they might appear at the same place anyway!? 


   
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(@vincent-mod)
Universe Admin
Joined: 7 years ago
Posts: 5707
 

Yes that's why darks work. If you make some proper darks a BPM will be made automatically as well, this you can use on all your data taken with the same sensor. It removes bad pixels and never hurts the data, so always use one is my advice.


   
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(@infoarnaldolopez-nl)
White Dwarf
Joined: 4 years ago
Posts: 14
Topic starter  

@vincent-mod from now on... I will 😉 Thanks for the advice!

 


   
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(@steveibbotson)
Red Giant
Joined: 7 years ago
Posts: 31
 

You could try some retrospective darks.


   
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(@vincent-mod)
Universe Admin
Joined: 7 years ago
Posts: 5707
 

Good suggestion Steve, you can try that indeed and make a bpm with those.


   
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(@infoarnaldolopez-nl)
White Dwarf
Joined: 4 years ago
Posts: 14
Topic starter  
  • @steveibbotson Indeed, I thought about that. I’ll give it a try! 

   
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