Quote:
Originally Posted by RickS
Greg, we're using RBI flush with a PL16803 at SRO now. The RBI flush actually adds additional noise. The current that leaks out of the traps after the flush, like any signal, has shot noise associated with it. What the flush does is prevent ghost images from previous exposures. It's not intended or expected to reduce overall noise.
Cheers,
Rick.
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Yes trapped charge leaks out during the exposure hence the need for high cooling to reduce the amount that leaks out. But the question really is do you notice any difference (improvement?). I am familiar with the RBI argument but if your tracking is very accurate and subs sit in the same spot image after image which they do when everything is schmick or if you dither and take enough subs then RBI would simply be either nonvisible in the first instance or an outlier in the 2nd instance.
If I flick through a long series of subs its hard to notice any artifact apart from cosmic ray hits. Where I do see it is if a plane flies through a sub or you take darks right after some lights which had some bright stars in it.
The worst I saw was when a plane flew through the image and the trailing lights were visible in the next 3 or 4 subs as it faded eventually.
Greg.