ROSAT Guest Observer Facility

ROSAT Status Report #73:

Nov 30, 1993


ROSAT Operations

ROSAT is back since Friday, Nov 26. MPE are currently working with a Sun angle in the range 85-95 degrees, except for observations during this current week, when ROSAT is in a full Sun orbit (i.e. it never enters the Earth's shadow). Operational experience so far indicates that all systems are working well and that we can acquire all targets. A problem area are Earth blocks on the night side; under these circumstances larger attitude drifts are observed which are not fully understood. There are also occasional short period losses of attitude which are under investigation, too. From December 5 onwards MPE will go back towards a 5 degree half angle sun cone. MPE will then try to insert a few observations with a larger sun angle and investigate the stability of the attitude system in order to find out which maximum sun angle is acceptable for safe operations. All current timelines allow slews to be performed only on the day side. This will also apply to the next long term timeline. Test runs show that this constraint leads to an average reduction in observing efficiency by 10 percent (in terms of the actually obtained observing time). The start of the next long term timeline or LTL (originally scheduled to begin on Dec 21) is extremely likely to be delayed until all necessary boundary conditions for scheduling have been determined. Until that time timelines will essentially be done "by hand", obeying the current sun cone requirement as well as the day slew requirement. The originally planned extra time program is cancelled since there is basically no extra time available (10 days of observing fully lost, reduced efficiency afterwards). TOOs can of course be accommodated in the usual way.

Menu Select another report ROSAT GOF Return to the ROSAT GOF Curator: Michael Arida (ADNET); arida@milkyway.gsfc.nasa.gov
HEASARC Guest Observer Facility


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This file was last modified on Tuesday, 14-Sep-1999 11:47:03 EDT

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