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Old 10-11-2018, 08:11 AM
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RickS (Rick)
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Join Date: Apr 2010
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Quote:
Originally Posted by Peter Ward View Post
All you need are 5 to 9 or so Median combined, auto dark subtracted sky flats (one set for each filter)
With a KAF-16803 and deep wells that will give you a total integration of around 200K or more electrons and pretty good SNR. With a CMOS camera at high gain it might only give you a few thousand e- and poor SNR. It's always a good idea to do the maths:

Total electrons = number of subs x 1/2 full well (assume you're doing flats at around 30K ADU)

SNR = total e- / sqrt(total e-) = sqrt(total e-)

Somewhere around 250K e- is a good number but possibly impractical with shallow wells. It's 6 subs with my U16M and 252 subs with my ASI1600mm at a gain of 200!

Cheers,
Rick.
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