Re-Calibrating Pre-COSTAR FOS Data

Howard A. Bushouse
Space Telescope Science Institute


FOS Instrument Science Report CAL/FOS-129
November 1994

 Abstract

A description of the methods by which pre-COSTAR non-polarimetric FOS data
may be recalibrated using the photometric corrections and calibrations of 
Lindler and Bohlin (1994) is presented. Recalibration is accomplished
through the use of the IRAF/STSDAS task calfos (version 2.0), which
includes corrections for deviations in OTA focus, changes in sensitivity
over time, and new inverse sensitivity data based on the switch from 
the IUE absolute flux scale in the UV to a model atmosphere flux 
distribution for G191B2B.