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.
