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|Description||Flat field image. Subtraction of the dark frame and flat field correction applied to the original, raw CCD image results in the final, calibrated image. The flat field image is recorded by pointing the instrument towards a unifromly illuminated surface. It records differences in the sensitivity of pixels, and vignetting in the optical path. The dark "doughnuts" are caused by dust specks on the CCD window.|
|Author||H. Raab (User:Vesta), Johannes-Kepler-Observatory, Linz, Austria (http://www.sternwarte.at)|
All images of the series showing the calibration of a CCD image:
GNU Free Documentation License
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