Analysis of Photometric Standards following
W	  July, 1992 FOS Overlight Safing Event

Cynthia J. Taylor and Charles D. (Iony) Keyes
Space Telescope Science Institute

FOS Instrument Science Report CALJFOS-086
December 1992


ABS TRACT

A comparison of flux-calibrated observations of photometric standards
G191-B2B (obtained in September, 1992) and BD+28D4211 (obtained in
June, 1992) has been performed in order to evaluate possible effects
of the July, 1992 overlight safing event on FOS sensitivity. The ratio
of G570H September /June count rate ratio to G650L September/June
count rate ratio shows that within formal errors there was no absolute
or wavelength-dependent degradation in instrumental sensitivity.