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Hubble Space Telescope
GHRS Instrument Science Report 060

GHRS Instrument Science Report 060

"GHRS Cycle 2 Sensitivity Monitoring Program 4124"

David R. Soderblom, Lisa E. Sherbert, Stephen J. Hulbert, and Claus Leitherer

Abstract excerpted from the report:

The GHRS observed the ultraviolet standard star u Col in late
September 1993 (Cycle 3) as part of a delayed Cycle 2 calibration
program. A comparison of those observations to spectra of the same
star obtained about a year earlier show that the sensitivity of
the GHRS has been stable to within better than 1%. The fluctuations 
about unity of ratios of measurements obtained at different times
indicate that a single observation of a star in the LSA has an
uncertainty in its flux due to mirror centering errors of about
1.0 %. This value applies to pre-COSTAR observations.