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Old 18-04-2015, 11:22 AM
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RickS (Rick)
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Join Date: Apr 2010
Location: Brisbane
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Nice images, Kevin!

Quote:
Originally Posted by cometcatcher View Post
Why the 30 second subs? Multiple reasons, first of all up here in hell, I mean the tropics, it gets hot and stays hot all night. According to the experiments I've done the single largest contributor to thermal noise when it's hot is time. 1 minute subs have twice the thermal noise at 30C of 30 second subs so why bother?
Twice the exposure time gives you double the thermal current but less than twice the noise. It's actually SQRT(2) or approximately 1.4 times. The big advantage of longer subs is that you start to overcome the read noise which is often considerable.

Cheers,
Rick.
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