Correcting for CCD Non-linearities
(based on Chapter 3 of Baldry, 1999, PhD thesis, Univ. Sydney)

Ivan K. Baldry $^{1,2}$

Timothy R. Bedding $^1$

Hans Kjeldsen $^3$

$^1$ Chatterton Astronomy Dept, School of Physics, University of Sydney, NSW 2006

$^2$ Anglo-Australian Observatory, P.O.Box 296, Epping, NSW 1710

$^3$ Institute of Physics and Astronomy, University of Aarhus, DK-8000 Aarhus C, Denmark

Abstract:

CCDs can deviate significantly from being linear detectors. We describe methods of accurately determining non-linearities, so that corrections can be applied to CCD data. Two CCDs that have been used on the 74inch Telescope at Mt. Stromlo Observatory are used as examples. They have a 5% and a 1.5% change in gain between 0 and 40000 ADU, which can degrade astronomical results if not corrected for.

Keywords: instrumentation: detectors -- techniques: image processing