INSTRUMENT SCIENCE REPORT CAL/FOS-006
	SPACE TELESCOPE SCIENGE  INSTITUTE
	

	
TITLE:	FOS Flat Field Calibration. (FOS Calibration #15)
AUTHOR:	D. Lindler and R. Bohlin	
DATE:	March 1984

ABSTRAC:

The FOS photocathodes have a granuiarity of less than one
percent. Eleven blemishes, with sensitivity variatjons greater than 5
percent, were found on the red tube in regions illuminated by aperture
A3. One blemish is a hat spot and has an increased sensitivity of
approximately 10%. ~Vhe spatial extent of the blemishes in the
direction of the diode array range from 50 to 250 microns. No data was
available for the blue tube in air becauge of schedule constraints. In
vacuum, only a minimal amount of data was obtained from the one
functioning Quantatec lamp (Krypton).