Quote:
Originally Posted by RickS
Hi Ray,
I definitely need flats with my KAF-16803. Interestingly, I take dusk and dawn flats every day when I have the scope set up in the back yard and I have found that having lots of flats does make a measurable improvement in SNR using PI noise analysis tools.
Richard Crisp did a flat field PTC analysis of one specific KAF-16803 and found that around half a million electrons was the sweet spot so that's what I usually target (around a dozen flats at 40K e- half well.) However, I recently discovered that if I use several times as many I can measure a significant SNR improvement. I must do some more PTCs myself when I get a chance. Maybe my sensor behaves differently to the one that Richard measured.
Cheers,
Rick.
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Richard recommends taking around 20 flats. That's why if you are taking dawn/dusk flats you need a camera with fast downloads. Otherwise you don't have enough time to capture that many for each filter.
Greg.