[daip] Potential LISTR Bug

[Eric Greisen]

Found it:

12506.  November 28, 2007        polarization cal            Eric
        A bug was discovered that caused polarization calibration to
        be incorrect when the calibration routines are initialized for
        a second time.  This is common - LISTR loops over IF with an
        init each time, SPLIT loops over source, UVPLT reads the data
        for scaling and checking before rereading for plotting, etc.
        The result is grossly wrong data because the polarization cal
        tables do not get reinitialized.  Fortunately, the bug applies
        only to non-approximate modes and then only when the
        parallactic angle does not change which would be rare except
        for equatorial telescopes which have no parallactic angle.
        Thus WSRT data are almost the only data affected by this bug.
        Changed DATPOL to init the "old" parallactic angle to an
        impossible value whenever the source changes.

The MNJ run tomorrow will fix the bug.

Many thanks for your diligence and help.

Eric Greisen