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Old 05-06-2016, 11:09 AM
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Slawomir (Suavi)
Amateur Photon Collector

Slawomir is offline
Join Date: Sep 2014
Location: Proserpine
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Originally Posted by Shiraz View Post
further to that, people have been looking at "amp glow" by stretching darks and noticing some variation in the bias/dark current, probably due to variations in Peltier temperature. What people seem to be neglecting is that the ADU values represent the 12 bit signal from the chip, multiplied by 16 to give the 16 bit ADU values in the subs. The glow that everyone keep quoting is actually on the order of maybe one or two electron or so in 300 seconds - it is the sort of fluctuation that could well be present in all cooled cameras, but this is the first one that has low enough read noise that you can actually see it. Rather than being a fault, it is an indication of just how low the noise is in this camera.

Such low read noise will easily show the slightest gradients across the chip.

I measured the 300s dark from ZWO website, and the difference in mean ADU value between the darkest and brightest regions in this 300s dark is 26 ADUs, so indeed very low in electrons.

For reference, I attached a result of an extreme stretch of the 300s dark from ZWO website.
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