FOC Instrument Science Report #085 15 Jan 1996 "Results of the Cycle 4 FOC DQE Program" by R. Jedrzejewski Abstract excerpted from the report: This report describes the calibration of the FOC+COSTAR DQE from in-orbit data. Two spectrophotometric standard stars were observed through many FOC filters to determine the absolute sensitivity. The data were analyzed in a significantly different fashion from earlier (pre-COSTAR) data, largely because of the smaller field of view of the COSTAR-corrected FOC. It was found that the (Observed/Expected) fluxes followed a linear relation with wavelength, and when the FOC DQE curve was corrected by this function, r.m.s. residual errors of only 6% in the absolute flux determination remained. Analysis of the ND filter transmissions did not show any significant differences between the observed and expected throughputs, although more work is needed to check this finding. The Pseudo-Strehl and FWHM performance characteristics of the FOC were measures and plotted to assist potential users, and a comparison of FOC and WFPC2 sensitivities in the ultraviolet shows that the FOC is significantly more sensitive for all wavelengths below 4000 Angstroms.
