GHRS Instrument Science Report 030 Preliminary Analysis of GHRS Resolving Power Loss due to OTA Spherical Aberration 06/90 Ronald L. Gilliland Abstract excerpted from the report: With the recent discovery that HST will not deliver image qualities near specifications, we must define the resulting impact on spectroscopic resolution and throughput. In the GHRS with apertures of 0.25" and 2.0" (SSA and LSA respectively) square, the impact is primarily: 1) in the SSA a throughput loss to 25% of originally expected sensitivity, or a loss of 1.5 magnitudes, and 2) a point source observed in the LSA will retain about 80% of expected throughput, but suffer a resolution degradation of about a factor of two.
