QL processing of POINTING observations REDUCE_POINTING_QL
For DREAM/STARE, the images from the individual subarrays are combined, sky emission removed (assuming a simple DC offset) and corrected for extinction.
SCAN-mode data are passed to the iterative map-maker. Fast-ramp flatfield files are processed and stored so the iterative map-maker can use them.
The image is cropped to 150 arcsec on a side and any residual background is removed (if necessary). If the source is a known calibrator, the pipeline calculates FCFs. The image is then calibrated and a flag flag file written to allow the POINTING_FOCUS task at the summit to derive pointing offsets.
For additional record keeping the source position is fitted to derive offsets in Azimuth and Elevation from the nominal (0,0) position. These offsets are written as a JCMT::Pointing extension in the coadd, and to a log file. Note, however, that these may not be identical to those derived by the telescope POINTING_FOCUS task. The recipe also determines the beam size and the flux conversion factor (FCF), which are also written to their respective log files.
The pointing offsets, beam size and FCF are written to the log files log.pointing, log.beam and log.fcf.
Fast-ramp flatfield data are processed and results written to the log file log.flatfield.
The pointing offsets are calculated from the centroid position and a fit to the source. They are written into the output file as a JCMT::Pointing extension as an initial guess for the POINTING_FOCUS task.