We envisioned that we could do two tests of the linearity of the CCD. An indirect test where we would test whether the conversion factor was constant with level, and a direct test where we would test whether the level per unit time was constant with level. Results from these two test are reported in Sect. and below.
For both purposes, 68 dome flats were taken, with an
attempted constant light source. 2 filters were used:
Johnson B (JB) and Gunn r (GR).
Only the section
(in untrimmed coordinates) was read out
(this should not affect the results).
All the images were taken in pairs with equal exposure time.
The exposure time was varied in on order to span the full range of the CCD
(0 - 65535 ADU).
In between every one or two pairs of exposures with varying exposure time,
a pair of exposures with exposure time 10 sec was taken.
The sequence of exposure times is shown in Table .
Properties of E and S0 Galaxies in the Clusters HydraI and Coma
Master's Thesis, University of Copenhagen, July 1997
Bo Milvang-Jensen (email@example.com)