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Basic Information on blcal


Task: blcal
Purpose: Compute and apply baseline calibration.
Categories: uv analysis

        BLCAL computes and applies baseline-based calibration to a visibility
        dataset.
 
        This reads two datasets. It uses the first dataset to determine
        baseline-based calibration, and applies these calibration corrections
        to the second dataset.

Key: vis
        Normally, this gives the name of two visibility datasets, being
        the "reference" and the "source" datasets respectively. The
        reference dataset is used to determine the baseline calibration,
        whereas the source contains the data that is corrected and written
        out. If only a single dataset is given, then this is self-calibrated.
        Baseline-based self-calibration is a very dubious operation, and
        generally should not be performed.
 
        Note: Both the reference and source datasets should be in time order.

Key: select
        The normal uv selection commands -- see the help on select for
        more information. This selection is applied to both the reference
        and source input datasets.

Key: line
        The normal uv linetype in the form:
          line,nchan,start,width,step
        See the help on line for more information.
        The default is all channels (or all wide channels if there are no
        spectral channels). The output will consist of only spectral or
        wideband data (but not both).

Key: stokes
        Normal Stokes/polarisation processing. See the help on stokes
        for more information. The default is to use the Stokes/polarisations
        present in the dataset.

Key: interval
        Solution time interval, in minutes. The default is a single solution.

Key: out
        The name of the output uv data set. No default.

Key: options
        Extra processing options. Possible values are:
          nopassol  Determine a solution which is independent of channel number.
          nopolsol  Solve for parallel-hand polarisations only. When
                    applying corrections, cross-hand correlations get corrected
                    with a parallel-hand gain. In particular XY and YX are
                    corrected with the mean of the XX and YY gains; RL and LR
                    are corrected with the mean of RR and LL gains; Q,U, and V
                    are corrected with the I gain.
          replace   Rather than writing the corrected dataset, write out a
                    dataset where the data are replaced with the model of a
                    unit point source with baseline errors.

Generated by miriad@atnf.csiro.au on 21 Jun 2016