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GHRS Instrument Science Report 037

GHRS Instrument Science Report 037

"GHRS Bright Star Target Acquisition After the Side 1 Loss"  1/29/92

Ron Gilliland

Abstract excerpted from the report:

With both Sides 1 and 2 available on GHRS there were no stars too bright
for routine target acquisition. Furthermore, there were no stars too 
bright for spectroscopy with any of the several modes on GHRS. The
very brightest stars would have been acquired with the attenuated
mirror on Side 1 (A1) even if the spectral observations were to use only
Side 2 elements. In Cycle 1 there are several GO and GTO proposals that
request acquisitions of stars that are nominally too bright for the Side 2 
attenuated mirror (A2).

It is the purpose of this memo to address:
   1.  What is the source of current bright star acquisition limits?
   2.  What stars can and cannot be acquired with the current system?
   3.  What changes to flight software and/or the ground control system
       would allow the very brightest stars to be acquired with GHRS in
       the future?
   4.  Current and future recommendations.