Revised FOS Wavelength Calibration


G. A. Kriss, W. P. Blair, and A. F. Davidsen
The Johns Hopkins University

Instrument Science Report CAL/FOS-054
November 1988



Abstract

In February 1988 the FQS was re-assembled at Lockheed and a new red
detector (F12) was installed in the FCS. Subsequent to installation,
new wavelength calibration data was acquired for eacb detector in
March 1988. In August 1988 the detectors were removed for installation
of new heat pipes. After the FOS was reassembled (including attachment
of the outer panels and the MLI. blanket) a full set of wavelength
calibration data was obtained once again. Since these calibrations
were obtained under ambient conditions, there is no data for the blue
H13 grating. Following the reduction procedure described in FOS
Wavelength Calibration (Sirk and Bohlin 1986, CAL FOS-026), we
determined new dispersion solutions for all dispersers for the blue
and red detectors. The blue detector shows only sli~ht differences
from tbe results in CAL/FOS-026. The new red detector has a higher
dispersion by -.4.5% from FS, and the dietortion terrns are
qualitatively different. For both the blue and red detectors the
internal errors of the dispersion solutions are -.-0.05 diodes or less
for the gratings, and ~ 0.1 diodes for the prisms.