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Dark frame issue with an ASI294MC Pro

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#1 kpopejoy

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Posted 16 May 2021 - 10:50 AM

I had my inaugural run with a new ASI294MC Pro this week. I noticed some interesting defects in my lights during preprocessing and investigated my dark frames and sure enough, there it was. I ran a new set with the camera off the telescope, sensor cover in place, and bundled in a towel. What do you make of this?

 

 

Attached Thumbnails

  • Dark_300.0s_Bin2_0001_thn.jpg

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#2 StarBurger

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Posted 16 May 2021 - 11:08 AM

I don't use this camera but I have seen enough (too many?) similar images here to understand that it is amp glow. Intrinsic to the camera and can be mitigated by appropriate darks.


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#3 hornjs

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Posted 16 May 2021 - 11:09 AM

What was the defect in your lights?  If you are referring to the multiple starburst areas, that is normal for this camera.  My darks look like this as well.  usually calibrates out just fine.  



#4 jdupton

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Posted 16 May 2021 - 11:30 AM

kpopejoy,

 

   We need a little more information.

 

   Is the thumbnail image you posted a single Dark frame or is that a Master Dark frame stacked from many individual frames?

 

   What exactly is the issue with your Light frames after calibration?

 

   As others have already mentioned, the starburst glow patterns at the right center and upper left are due to "Amp Glow" -- essentially IR radiation from a portion of the sensor itself. That is completely normal and should calibrate out when Dark frames are applied to the Light frames. The calibration should remove this completely. If it doesn't, we would need to more lots more about your calibration methodology -- which software you use, how was the Master Dark prepared, whether the Dark frames matched all capture parameters with the Light frames, etc.

 

   If, on the other hand, you are asking about the dark horizontal lines in the Dark frame, this is another common question about this camera. There are quite a few threads here on CN about the Dark Banding issue and how to minimize or eliminate it.

 

   Tell us more about your concerns and perhaps we can steer you to a remedy.

 

   By the way -- Welcome to Cloudy Nights! I see this is your first post although you have probably been reading for a while judging from your join date.

 

 

John

 

 

[Added EDIT]

 

Oops, I just noticed that you are using the OSC version -- ASI294MC-Pro. My mistake -- I thought you were asking about the monochrome version at first. The ASI294MC-Pro camera does not usually show the dark banding issue seen in the ASI294MM-Pro (a totally different camera in spite of the similar name).

 

The starburst glows you see are totally expected and with proper application of Master Dark frames, should never show in your calibrated Light images.


Edited by jdupton, 16 May 2021 - 11:52 AM.


#5 BKMaynard

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Posted 16 May 2021 - 11:45 AM

Amp glow
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#6 kpopejoy

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Posted 16 May 2021 - 12:36 PM

Thanks for the clarification on amp glow. This is my first dedicated astronomy camera and I was hoping for a simple answer. The final image came out fine.


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