Calibration Access and Data Handbook
Previous: Generation from Ground Calibration
The degradation correction coefficients have been calculated by a linear
fitting to the measured counts (coincidence loss corrected) of the stars
BPM 16274, Hz 2 and GD 153 observed periodically since the beginning of
the mission. The fit is done for each filter as a function of the MJD of
observation, using the data of all stars. These stars are observed once per
year (BPM 16274 twice) to monitor the variation of sensitivity.