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6.1 FOC Pipeline Processing

All data received by STScI from the Space Telescope Data Capture Facility pass through the Observation Support and Post-Observation Processing Unified System (OPUS)-referred to as the pipeline-to be processed and calibrated. The calibration software the pipeline uses is exactly the same as that provided within STSDAS under the hst_calib package (calibration software for Faint Object Camera is in the subpackage stsdas.hst_calib.foc.focutility.calfoc), enabling you to recalibrate any FOC data just as the routine calibration pipeline does. The calibration files and tables are taken from the Calibration Data Base (CDBS) at STScI and are usually the most up-to-date calibration files appropriate for the instrumental configuration used in the observation. (For additional details on the reference files used in the past, see also FOC Instrument Science Report (ISR) 082, available through the FOC pages on the World Wide Web).

The FOC calibration software (calfoc) takes as input one image: the raw .d0h file, and it produces two output images:

A geometrically corrected image (.c0h).
A geometrically corrected and flatfielded image (.c1h). In addition, the calibration software takes as input any necessary calibration reference images or tables, and some engineering files. The calibration software determines which calibration steps to perform from the values of the calibration switches in the header of the raw data (.d0h) file (see also Table 6.1). Likewise, it selects the reference files to use in the calibration of the data by examining the reference file keywords. The appropriate values of the calibration switches and reference file keywords depend on the instrument configuration used, the date when the observations were taken, and any special pre-specified constraints. These parameters were set in the headers of the raw data file in the RSDP pipeline during the creation of the .d0h image.

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