Michael R. Rosa (STECF (Space Telescope European Coordinating Facility), c/o ESO, Garching)
Predictive calibration methods, based on physical instrument software models are being developed primarily with a view to optimize the scientific return of contemporary and future instruments. At the STECF several packages devoted to the optical and electronic performance of spectrographs and their detectors are being employed now to a large scale review of the entire science and engineering data archive of the Faint Object Spectrograph (FOS), in operation till end of 1996 onboard the HST. The goals are a thorough cleanup of the FOS calibration leading to an improved post operational archive, combined with the field testing of instrument model software and automomous boot strap calibration methods. The paper will combine a discussion of the principles of predictive calibration and its application with detailed examples of optical models and instrument environment modelling (geomagnetic field, HST orbital models) from this FOS post operational archive project.