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Question about these dark circles in my image

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#1 GKSAstro

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Posted 28 November 2021 - 09:26 PM

Hello

 

I just got a ZWO ASI183GT and ZWO LRGB filters running on a Redcat 51. I noticed with some test shots and this shot below that there are two dark circles, one is fainter than the other. Would anyone know if  hese are reflections from the ZWO filters or what is causing this?

 

Thanks

Greg

 

 

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  • combine-RGB-image-St002-Edit002 copy 2.jpg


#2 qswat72

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Posted 28 November 2021 - 09:34 PM

Looks like a dust mote on either the sensor or one of the filters.
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#3 OldManSky

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Posted 28 November 2021 - 11:35 PM

Yep, dust.  

a) clean your optics (camera window, filters).  

b) take flats -- they'll correct for dust you couldn't get rid of or didn't want to bother with.



#4 GKSAstro

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Posted 29 November 2021 - 12:34 AM

Thanks guys,

 

I did not think that was dust due to the size and perfect circle nature of them. I cleaned it off again and took some test shots. Not seeing the circles anymore.



#5 GKSAstro

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Posted 29 November 2021 - 12:36 AM

Since I cleaned it off after the initial photography session, would shooting flats remove the circles after the fact or am I out of luck now?



#6 DivisionByZero

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Posted 29 November 2021 - 12:41 AM

You're out of luck. Flats have to be taken very close to the lights because the dust can move. Since you cleaned and moved the dust you can't calibrate any longer.


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