National Radio
Astronomy Observatory

1.6.3.4 Polarization Calibration

The polcal task will solve for any unknown polarization leakage and cross-hand phase terms (’D’ and ’X’ solutions). The ’D’ leakage solutions will work on sources with no polarization and sources with known (and supplied, e.g., using smodel) polarization. For sources with unknown polarization tracked through a range in parallactic angle on the sky, using poltype ’D+QU’, which will first estimate the calibrator polarization for you.

The solution for the unknown cross-hand polarization phase difference ’X’ term requires a polarized source with known linear polarization (Q,U).

Frequency-dependent (i.e., per channel) versions of all of these modes are also supported (poltypes ’Df’, ’Df+QU’, and ’Xf’.

See § 4.4.5 for more on polarization calibration.

More information about CASA may be found at the CASA web page

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