UPDATE: Automatic scheduling of CAM-CVF observations to be
Resumed
The mission planning software has now been updated to
prevent an SWS observation following a CAM-CVF one more closely than 30
mins; this software will become operational on 22 September and full automatic
scheduling of CAM-CVF observations will then be resumed.
Martin F. Kessler,
12 September 1997.
CAM CVF Observations Influence SWS Dark Currents
Trend analysis has shown that CAM-CVF observations (AOT
CAM04) can raise the temperature of the structure that supports all four
instruments. This rise is sufficient to cause an increase in the dark currents
of the SWS band 3 (12 - 29 um) detectors. While it is not thought that this
increase impacts the signal- to-noise of the SWS observation, it complicates
the dark current subtraction and may well reduce the accuracy of the flux
calibration.
Thus, it has been decided that no SWS observation should be scheduled
within 30 mins of a CAM04 AOT.
A software update to the Mission Planning is necessary for long-term
implementation of this decision. In the short-term, CAM-CVF and SWS
observations
will be kept apart manually. To achieve this, all CAM04 observations in
the Mission Data Base have been "blocked" from the automatic
scheduling
routines and will, as necesary, be scheduled manually at the end of the
daily scheduling periods. The status of CAM-CVF observations with fixed
time constraints and/or on targets located in closing sky bins will be
carefully
monitored to prevent and observations from being lost due to this temporary
blocking.
Martin F. Kessler,
ISO Project Scientist.