color dots on photo
 
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color dots on photo

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(@ofergol)
Red Giant
Joined: 4 years ago
Posts: 27
Topic starter  

Hi,

yesterday I started taking subs of M101.

After 60x60sec subs I decided to check the result so far (because m101 was almost unseen on single subs and I wanted to confirm my position).

Calibrated with flats and bias, I got an image with a lot of color dots that seems to run from left to right (the dec orientation of the frame).

Help on this issue is much appreciated.

Thanks

m101

   
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(@wvreeven)
Quasar
Joined: 6 years ago
Posts: 2133
 

@ofergol Hi Ofer, those colored dots are hot pixels which you can get rid of by using darks as well.


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

Yep, Darks and dithering!


   
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(@ofergol)
Red Giant
Joined: 4 years ago
Posts: 27
Topic starter  

Thanks.

I added darks and got a strange error message (attached).

error message

What am I doing wrong? 


   
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(@wvreeven)
Quasar
Joined: 6 years ago
Posts: 2133
 

@ofergol Do the flats and darks have different gain, offset and/or temperature?


   
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(@ofergol)
Red Giant
Joined: 4 years ago
Posts: 27
Topic starter  

I think all parameters are the same.

Log files for light/flat/dark are attached.

light log
dark log
flat log

 


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

0.03 seconds is too short for a flat, you need to get that up to 1-2 seconds preferably. You also need a masterbias or darkflat to correct them with the same exposure length as the flat.


   
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