Quote:
Originally Posted by gregbradley
I find median combine works best for combining images.
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Median combine naturally rejects outlying pixel values but produces lower SNR than an average combine (about 20% less.) Average combine with careful rejection can give you the best of both worlds.
Quote:
Originally Posted by jase
Yes, but in order to determine the right value you need a PTC for your camera. As Richard's paper mentions, you don't want to be taking flats in the ADU range where the camera goes non-linear. Its just before that to maximise signal and suppress noise.
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A flat field PTC will also allow you to figure out how many flats are enough. In the case of my KAF-16803 the sweet spot is around 500,000e- which is around 12 flats at half full well.
Cheers,
Rick.