Specifications

If we take images for individual colors and also luminance image, possibly with
different binning and exposure times, the calibration starts to be relatively
complex. We need dark frame for every exposure time and binning. We need
flat field for every filter and binning. We need dark frames for every flat field.
This is the price for beautiful images of deep-sky wonders.
Color images with color camera
Single-shot color cameras use special CCD detectors with red, green and blue
color filters applied directly on individual pixels. G2 CCD cameras can be
equipped with such detectors (the name of the camera is then followed by the
letter “C” to indicate color CCD).
Every pixel receives light of particular color only (red, green or blue). But color
image consists of pixels with all three colors specified. So it is necessary to
calculate other color from the values of neighboring pixels.
Covering pixels with such color mask and subsequent calculations of remaining
colors was invented by Mr. Bayer, engineer working at Kodak company. This
is why this color mask is called Bayer mask and the process of calculation of
missing color is called Debayer processing.
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Illustration 24: Schematic diagram of color CCD detector