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Old 19-04-2021, 09:54 AM
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Tinderboxsky (Steve)
I can see clearly now ...

Tinderboxsky is offline
 
Join Date: Feb 2012
Location: Kingston TAS
Posts: 803
Thanks Chris. I have Bortle 3 to 4 skies and I'll do the analysis for here.



Quote:
Originally Posted by ChrisD View Post
I'm no expert, but this is how I look at this problem.

Reducing the temperature of the sensor will reduce the noise created in the sensor, (Dark Current) but by how much and will you see it?

Well, I've attached the Dark Current v Temperature graph for the ASI294MM pro (the MC should be the same).

The value of dark current (noise) is given in Electrons/second/pixel.
So, by the graph, at 0 degrees you will get about 0.02 e/s/p

So how does that compare to other noise sources?

Well the major source of noise in an image is sky glow.
If you go to:
http://tools.sharpcap.co.uk/
you can enter you camera, scope details, and Bortle value and get the sky glow e/s/p value.

I'm Bortle 5 with a ASI294 and a C8 I get around 0.69 e/s/p from sky glow


So, for me, if the camera was at 0 degrees, I would get 0.71 e/s/p of total noise from the 2 sources (skyglow and dark current) with just 2.8% being from dark current itself.

I don't think cooling would make any difference, the noise from sky glow swamps the noise from the uncooled sensor in most cases.

You probably have better sky than Bortle 5 but you can run the figures now and make your own value judgement.

Chris
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