Joint GHRS/FOS Instrument Science Report

(= GHRS Instrument Science Report 66)


July 1994



Comparison of the Low-Resolution Mode of the GHRS and the
High-Resolution Modes of tbe FOS


Claus Leitherer and Anne Kinney

Abstract. The waveleiigth region betweexi 1150 Ä and 1900 Ä can be
observed with the GHRS and the FOS with similar spectral
resolution. The advantages of using either the GHRS with tlie G14OL
grating or the FOS with the G13OH aud G19011 gratings are
discussed. We address instrumental overheads, target acqlnsitiolls,
sensiti~rity, scattered light, wavelen.gth coverage, aperture sizes,
and spectral resolution. In general, if observations at wavelengtlis
below 1500 Ä are the prime scientifk goal, tlie GHRS is more sensitive
and bas better spectral resolution. At longer wavelengths, the FOS
will give better scientific return.