CCDs characterization is the preliminary step to perform before the CCD can be prop¬erly used at the telescope.
Most of the scientific instrumentation at the Italian National Telescope "Galileo" use CCDs as detectors. In particular the optical imager (OIG) and the high resolution spectrograph (SARG) use a mosaic of two 2k x 4k CCD manufactured by EEV (EEV 4280). The technical characteristics of the EEV4280 can be found in Cosentino et al (these proceedings)
