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Session 39 - Observing with HST.
Display session, Tuesday, January 16
North Banquet Hall, Convention Center
The HST Long Range Plan (LRP) is a timeline containing the planned scheduling opportunities for most HST observations. An accurate, stable LRP is important in that it allows observers and observatory staff to effectively allocate their work. In addition, it provides a comparative baseline for the execution progress of the science program and can be used to assess the impact of spacecraft and instrument anomalies. In November of 1993, the PRESTO began the task of re-engineering the LRP system in an effort to increase the stability and accuracy of the plan.
Prior to cycle five, the HST LRP assigned each observation to a specific week during the cycle. However, due to a variety of reasons many observations could not be scheduled in their planned week and had to be re-planned, causing the plan to be unstable.
The new method that has been implemented assigns a plan window to each observation rather than a restrictive one week interval. The plan window is a subset of the observing opportunities dictated by the scientific and spacecraft constraints. For most observations, the plan window is a continuous eight week interval. But because of its constraints, a particular observation's plan window can be shorter than eight weeks or it may be a set of several small windows within an eight week interval.
This paper focuses on the practical issues of plan windows that are relevant to the HST observer. The topics that are discussed include which observations receive plan windows, how plan windows are assigned, what can cause changes to the plan windows, and how to access plan window information via the World Wide Web.
