UC: ApplyPolarizationCalibration -------------------------------- S.T.Myers revision 2000-10-17 This pipeline task calibrates data taken in full polarization mode (with cross-hand products) in quasi-real time, in an automatic way, taking input data from the raw data archive, using antenna polarization objects from calibration archive. Role(s)/Actor(s): Primary: ALMA Archive System Secondary: AOS, Operator, Staff Astronomer, Observer Priority: Major Performance: seconds Frequency: minutes to hours Preconditions: 1. correlator data for a target experiment is available, taken in full (cross-hand) polarization mode 2. valid polarization calibration objects are available in the Calibration Archive Basic Course: 1. this task is meant to be carried out by the pipeline as part of an overall reduction sequence and is unlikely to be carried out on its own 2. the antenna polarization calibration parameters are retrieved from the Calibration Archive and applied to the data, likely in the form of a calibration table attached to the dataset Exception Course: there is no valid calibration available 1. the archive system notifies the appropriate contact about the failure, and possibly a suitable calibration schedule is generated for the dynamic queue 2. processing of this data may be deferred if deemed critical Postconditions: 1. the calibration is applied in the form of a table attached to the data 2. logs are written into the Science Archive Issues to be Determined or Resolved: 1. Will calibration be carried out by the attachment of a table to the data? 2. What are the criteria for acceptable calibration data - namely how close bracketed need the observation be (eg. within 7 days, 14 days, 30 days, 60 days), need all antennas have updated calibration (after a recent refit or move)? What is the appropriate action on missing calibration? 3. What feedback mechanisms are there for identifying possible calibration problems (eg. poor polarization images) which might warrant investigation or recalibration? Notes: 1. I am assuming that this UC is carried out as part of a higher-level calibration UC. 2. Only calibration suitable for a priori corrections can be applied in this manner - for example the polarized primary beam corrections for extended sources must be done as part of the imaging process. This limits the application of this Use Case to the polarization correction at the center of the beam. Created: 2000/10/10 smyers Revised: 2000/10/17 smyers