The horizontal dotted-dashed line shows the adopted value of the CCD scale of 0.5073 ''/pixel. This is actually not a mean of all the data, but only of 6 images on which astrometry was done at an earlier point. However, this value is very representative for all the data, as the figure shows.
Properties of E and S0 Galaxies in the Clusters HydraI and Coma
Master's Thesis, University of Copenhagen, July 1997
Bo Milvang-Jensen (firstname.lastname@example.org)