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When doing wide field shots, how much do some clouds get averaged out?

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#1 rj144

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Posted 04 March 2021 - 03:56 PM

So far, I've mostly tried narrow shots and when it's partly cloudy, the clouds typically just ruin a few frames (as they are about the size of the frame) and I discard those from being stacked.

 

The questions is if I do fairly wide field (like 50 to 70 mm), and it's partly cloudy, there will most likely be some clouds in some part of almost every sub (because of the wide field).  So, if they are small (compared to the frame), will they average out when stacked or do I need to wait for it to be completely clear?


Edited by rj144, 04 March 2021 - 03:58 PM.


#2 Jim Waters

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Posted 04 March 2021 - 04:05 PM

Depends on the cloud type, size, movement...etc.  There's no way to answer your question.  Do not do wide-field astro work when clouds are in your FOV.


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#3 rj144

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Posted 04 March 2021 - 04:10 PM

Depends on the cloud type, size, movement...etc.  There's no way to answer your question.  Do not do wide-field astro work when clouds are in your FOV.

Thanks, but if they are small, they must average out over a large number of frames.  They're a different kind of "noise".



#4 AstroBrett

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Posted 04 March 2021 - 05:35 PM

If they are moving fast and are not back lit, it is amazing how much can be removed by processing. Nevertheless, each image like that degrades the final result slightly, so you are best to avoid them. But you can process them out and salvage a night's work when you need to. You still need a number of good frames to work with,

 

Brett


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#5 imtl

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Posted 04 March 2021 - 05:41 PM

With high cirrus clouds it will reduce SNR and could be quite significant. The problem gets more complex when you got some serious light pollution as well since they will reflect the glow and swamp your signal even more so.


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