Quote:
Originally Posted by codemonkey
I've been thinking about this recently... In the above example, the signal is present in just over 2% of the subs. You'd be at risk of these being rejected in the stacking process by the same rejection parameters that protect you from sat trails and cosmic rays, so unless you were to go with a straight average (i.e. no rejection), there might still be a benefit in longer subs for very weak signals.
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Lee,
The dimmest target I've managed is the jet, R4 in NGC 1097. I don't remember the actual numbers but it was at the level where you could count the photons on your fingers in a 15 minute sub and the number of e- measured was less than the read noise. Through the magic of stacking I got a faintly visible signal and pixel rejection wasn't a problem.
Cheers,
Rick.