Basic Information on transfix

Task: transfix
Purpose: Correct for leakage near transit of DEC ~ -30 sources.
Categories: uv analysis

        This corrects for polarisation leakage caused by errors in
        the ATCA antenna orientation. The importance of this effect
        goes inversely with the square of the difference of the source
        declination from -30. It is most extreme at transit.
 
        To run this task, you must have the pointing parameter file used
        at the ATCA during your observation.
 
        To first order, it is not too important whether this correction is
        applied before or after gpcal is used, particularly for sources
        very close to DEC=-30. Some experimentation might be helpful.

Key: vis
        The name of the input uv data set. No default.

Key: select
        The normal uv selection commands. The default is to select everything.

Key: line
        The normal uv linetype in the form:
          line,nchan,start,width,step
        The default is all channels. Note that if there are multiple
        spectral windows, the fitting process is performed on each window
        separately.

Key: pparams
        Pointing parameter table. These tables are stored on the observing
        machine at Narrabri in the file pparams.log.
        The actively used version is:
        /atomsexport/caobsonline/caobs_pparms/pparams.dat
        Previous versions of the file are archived here:
        /archive/backup/caobsonline/caobs_pparams/pparams.dat.yyyymmdd-hhmm
        It is usually entered as an indirect parameter file.
        The table consists of 6 lines (one per antenna),
        each consisting of 12 numbers (the first number being the
        antenna number).

Key: options
        Task enrichment options. Possible values are
          replace  Replace the XY and YX correlations with an estimate
                   of the error. This option is only meaningful for
                   a polarisation-calibrated unpolarised dataset.
        Additionally there are the standard options to turn off calibration:
          nocal    Do not apply antenna calibration.
          nopol    Do not apply leakage correction.
          nopass   Do no apply bandpass calibration.
 

Key: out
        The name of the output uv data-set. There is no default name.