GHRS Instrument Science Report 068 "FOS-Assisted GHRS Target Acquisition" 11/94 Claus Leitherer, Anuradha Koratkar, Olivia Lupie and Steve Hulbert Abstract excerpted from the report: We describe the results of a test in which blind offsets between the 4.3" aperture on the blue side of the FOS and the GHRS Large Science Aperture were performed. The goal of this test was to demonstrate that the FOS can be used to acquire faint targets for subsequent spectroscopic observations with the GHRS. The test was successful. Three different stars were observed. They were found to be offset from the PDB position of the LSA by 0.2" ± 0.1" and 0.0" ± 0.1" in V2 and V3, respectively. It is recommended to offer this capability to observers using the GHRS who would otherwise not be able to acquire their target. The possibility also exists to offset targets from the GHRS to the FOS apertures. However, the magnitude of the uncertainty in the position of the GHRS LSA aperture (0.1") is large enough that a direct acquisition of a target into the FOS apertures would not be efficient.
