FOC Cycle 5 Calibration Plan
Calibration Summary
The performance of the FOC+COSTAR system has been characterized in detail using a
combination of ground-based and in-flight tests. After COSTAR deployment, an
extensive calibration program was carried out (SMOV) to describe the performance
of what could be considered, to all intents and purposes, a new instrument. At
that point, the scientific program was enabled. The Cycle 4 calibration program
then completed this initial effort and fully characterized the FOC+COSTAR
performance. In Cycle 5, we are in a routine situation, and our calibration
program is divided into two parts:
- a set of monitoring tests, whose aim is to maintain the calibration level
previously achieved (e.g. pointing accuracy, geometric distortion, flat fields), or
- to discover possible variations in performance
a number of dedicated tests designed to maximize the scientific output of the
instrument.
These tests were designed after having carefully reviewed the observing proposals
to be executed during the current cycle, and would, for example, provide accurate
PSFs and check the detector response at certain wavelengths, or characterize special
capabilities not previously calibrated. In the
calibration summary table
[PostScript, 48 kb],
we provide a list of the calibration tests which are being performed in Cycle 5,
with their objective outlined. For example, a significant number of FOC users in
this Cycle are using the polarizers, and therefore an extensive calibration program
has been designed, after checking all the individual requirements, to ensure that
the best science is achieved with the FOC polarizers.
- The Routine Calibration Programs
- The routine calibration programs are designed to monitor those aspects of FOC
performance that are believed to be subject to time variation. Typically, observations
are made at 3 month intervals to verify that the performance has not changed
significantly, and then warn users if a significant difference is found.
- The Special Calibration Programs
- The special calibration programs are designed to offer a more detailed calibration
of modes or observation types and represent a class of calibration observations that
may be executed once with the results expected to be valid over a long time base.
Previous special calibrations, as well as monitoring programs, have resulted in
calibration accuracies as discussed in the next section.
Should your program require calibration accuracies that are not obviously satisfied
by the values listed in the FOC Handbook, then you should contact an FOC Instrument
Scientist for guidance. Individual GO programs requiring special calibrations must
directly request these observations as part of their Phase I proposal.
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