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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 LEON at
Narrabri in the file at$log:pparams.log. 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.