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Old 06-12-2019, 12:41 AM
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The_bluester (Paul)
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Join Date: Feb 2011
Location: Kilmore, Australia
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Just to add to what I wrote, I found a post on CN which stated what I am thinking in perhaps clearer terms.

If you have an ADC with significantly fewer discrete levels than the pixel electro count then by reducing gain reduces precision in the data as it is effectively division with rounding and the net effect is a noisier output. I could certainly see that in the faint stuff when I used to run at zero gain and even ZWO’s specs seem to support that with approx 7.5e read noise at lowest gain versus around 1.5e at higher gain. The trade off for me has been flat looking stars versus noisy looking background and more noisy faint signal.
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