GHRS Instrument Science Report 036 "GHRS 3385: Absolute Sensitivity Monitor" 2/10/92 L. Walter and R. Gilliland Abstract excerpted from the report: The sensitivity of the GHRS in recent observations (CAL 3385, SV 3408) at 5 wavelengths for 3 gratings and at the blaze peak of 6 orders in Echelle-B were compared with previous measurements published in he GHRS Instrument Handbook V3.0. Sensitivities were obtained at the wavelengths 1200A, 1500A, 2000A, 2500A, and 3000A from observations of the standard star BD+28D 4211, and for Echelle-B at the blaze peak of orders 19-21 and 26-28 using Mu Col. The new calculations show an increase in sensitivity of 1.8+/- 3.6% in the gratings. The echelle sensitivities show increases of 7.5+/- 2.8%. Also compared were the target acquisition flux measurements for the mirrors A2 and N2 with respect to SYNPHOT predictions using the new mirror effective areas as published in V3.0 of the Handbook. The measured values differ by 0.2+/- 2.1% relative to the SYNPHOT predictions.
