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Well, the thing that most people focus on is the pixel count, but more important than that is the pixel SIZE. Not only is the pixel size closely related to sensitivity and signal to noise ratio, it should also be considered in comparison to the spot size of your telescope. That is, if the smallest spot the optics can produce is 10 microns a camera with 5x5 micron pixels would have around 4 pixels responding to a well focused star. That is called "over sampling" and is much preferable to the opposite. Or put another way, a camera with 20 x 20 micron pixels might have terrific specs, but you won't actually achieve good results if the star image covers only 10 microns - it would be under-sampled and since only part of the photo site is illuminated, the output would be weak. My QSI 583 has 5.4 micron square pixels and under the best conditions I have seen the FWHM get close to 1 pixel, but most of the time seeing makes it more closer to 2 pixels. I think that is about ideal, but suspect that some people would argue for more over-sampling.
Other than noise levels and dynamic range, are there any other chief "stats" that I should be aware of when buying a camera (CCD or CMOS)?
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