What is the observation time precision?
A given sky position cannot be observed at an arbitrary time. Even during the period when the sky position is available, observation times are limited to times the spacecraft is in eclipse and out of the South Atlantic Anomaly (SAA). Thus a series of observations which require highly precise observation times, perhaps to fulfill a specific sampling strategy, may or may not be achievable. The entire GI program must be planned together with the PI observations before specific observation times are known. Small numbers of individual eclipses — e.g. to catch a target of opportunity — can be scheduled with an average precision of about 35 minutes (roughly the average time to the next eclipse) when the target is observable. (Details in phase 2, see FAQ 114.) Also note that once a time-critical observation is assigned a given eclipse and the mission planning software sets the start and stop time to the exact second, we only have absolute knowledge of the observation start and end times to b
