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    Re: Calibrating New 24MP DSLR Canon Rebel for CN
    From: Peter Monta
    Date: 2020 Aug 20, 05:03 -0700
    Hi Greg,

    Good news about the camera.  For calibration, an image of a star field can work quite well.  If you'd like, I could process an image from your camera to obtain the plate scale and any small nonlinear distortion away from the ideal gnomonic.  One image of the stars near zenith (say within five or ten degrees) would be fine, with exposure time 1/2 second for the 200 mm (and inversely proportional to focal length for any other lenses), and maybe one stop down from wide open, or whatever your preferred aperture might be.  Would need the RAW format, i.e. Canon's CR2, not JPEG.

    Coincidentally, I've been working on lunar camera images recently.  I've got an automated scheme for finding the Moon's center to about 4 arcseconds standard error.  Once I've got the code cleaned up I'll describe in more detail.


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