INSTRUMENT SCIENCE REPORT CAL-FOS-007

TITLE:	FOS Scattered Light Measurements (Cal. Plan #12B>
AUTHOR: J. Wheatley and R. Bohlirt	
DATE:  March 1984



ABSTRACT:

The scattered liqht measurements in the dispersion direction are
reported incorrectly in the memo of 11/7/83. Table 1 of this report
replaces Table 2 in the previous memo. A corrected report follows.


Line profiles of two isolated spectral lines emitted by a 60 Hz
Mercury lamp were obtained on 29 October 1983. Each line was isolated
with a narrow band filter. Because the wings of the spectral line are
too faint to be captured on an unsaturated exposure of the peak, a 25s
exposure with the 1~0 circular aperture was made for the wings, and a
ls exposure with the 0~l aperture captured the peak. The peak count
rate in the 2536.5 A line is 24,000 cts/s. However, because the lamp
output is pulsed, the count rate during the lamps oncycle may be much
higher, requiring a substantial correction for the detector non
linearity. ExaminatiOn of two exposures made at different lainp
brightnesSeS suqgests that the true peak count rate in the 2536A
exposure is approximately 50,000 cts/s with the 0~1 aperture. The
4358.3A line, on the other hand, has a peak count rate of 3800 cts/s,
for which the above effect is less than 5%.