FIT

        [CLEAN\]FIT [Field]

    Fit the dirty beam to obtain the clean beam parameters.   This  is  done
    automatically by CLARK, HOGBOM, MRC and SDI if needed.

    Clean beam parameters can also be specified by the users, by setting the
    variables  MAJOR_AXIS,  MINOR_AXIS and ANGLE. In this case, no automatic
    fit will be perform by CLARK, HOGBOM, MRC and SDI.

    In mosaic mode, you can specify on which field the fit has to  be  made,
    using the first argument.