Laboratory Calibration of FOS Throughput
George Hartig
Space Tetescope Science Institute

Instrument Science Report CAL/FOS-053
January 1989



Abstract


Significant changes have been made to tbe FOS optical and detector systems 
since the previous absolute throughput measurements were reported. New 
calibration data were obtained, in ambient, in March and August, 1988, 
following these modifications. While the blue side efficiencies are slightly 
greater than those measured in 1984, marked improvements have been made in 
the red side throughput, as a result of detector replacement, optical 
realignment, and re-coating of the collimator mirror. However, FOS model 
calculations continue to overpredict the throughput of both sides of the 
spectrograph, in a wavelength independent manner.