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2022-05-29: APP 2.0.0-beta2 has been released !

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Strange trails or (bad?) pixels


(@infoarnaldolopez-nl)
Brown Dwarf Customer
Joined: 2 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

2F809BF8 6A65 42F9 B381 33959F58DFA8

 

This topic was modified 2 years ago by Arnaldo Lopez

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(@vincent-mod)
Quasar Admin
Joined: 5 years ago
Posts: 4830
 

Very likely yes, these can be bad pixels.


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(@infoarnaldolopez-nl)
Brown Dwarf Customer
Joined: 2 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)
Quasar Admin
Joined: 5 years ago
Posts: 4830
 

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)
Brown Dwarf Customer
Joined: 2 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)
Quasar Admin
Joined: 5 years ago
Posts: 4830
 

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)
Brown Dwarf Customer
Joined: 2 years ago
Posts: 14
Topic starter  

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

 


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(@steveibbotson)
White Dwarf Customer
Joined: 5 years ago
Posts: 31
 

You could try some retrospective darks.


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(@vincent-mod)
Quasar Admin
Joined: 5 years ago
Posts: 4830
 

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


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(@infoarnaldolopez-nl)
Brown Dwarf Customer
Joined: 2 years ago
Posts: 14
Topic starter  
  • @steveibbotson Indeed, I thought about that. I’ll give it a try! 

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