Maintaining Scheduling Efficiency in a
Two-Instrument Environment:
Reducing the Competition for SAA-Free Orbits

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J. Biretta, W. Kinzel, M. Reinhart, B. Whitmore, and J. Younger

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Abstract

An ad hoc working group met in October and November of 1998 to discuss the effect on HST scheduling efficiency of both STIS and WFPC2 competing for the same SAA-free orbits after NICMOS end-of-science. If nothing were done, the HST observing efficiency would decline from ~45% to ~27% from November 1998 to June 1999. We discussed possible changes in the ground system and in some of the observing programs to prevent this inevitable decline in observing efficiency if no action were taken. Out of the five options discussed, three have been implemented: reducing the size of the WFPC2 SAA-avoidance contour, restricting WFPC2 alignment times to 22 minutes or less whenever possible, and, unless scientifically justified, restrict all visit durations to no more than 5 orbits.