[evlatests] Multiple System Failures

[Ken Sowinski]

On Mon, 2 Jan 2012, Rick Perley wrote:

>    2) Referenced pointing failed twice -- on 3C138 and on J1118+1234 --
> the source I use for Mars.  The first failure is easy to explain -- the
> antennas were busy unwrapping, so of course we were not on the source.
> (A added curiosity here however -- bdf2aips filled the pointing data
> even though we weren't on source.  For the four successful pointing
> determinations, bdf2aips did not fill the data.  Apparently, it is
> sensitive to whether the antennas are actually on source or not.)
>    The second failure is more worrisome.    The Mars observation also
> required a modest slew -- about three minutes from 3C138 (which, it
> should be noted, the antennas never reached before the allotted time was
> up).  Yet I am confident we reached Mars before the pointing solution
> started, since I have 65 seconds of unflagged data on Mars at L-band.
> (Note, however, that at L-band, there is not enough flux to actually
> know if we're on the source -- I have to trust the antenna flags to
> justify the statement made above).  Now, the time spent on Mars at
> L-band was far too long -- I requested 15 seconds of 'on source', but
> got more than 65.  There was then a gap of the appropriate length for an
> X-band pointing determination, after which the normal sequence of
> observations began again.

There were no poinitng solutions for J1118+1234 because antsol
did not converge (or had no data) for subbands 0 and 1
(Widar notation) and subband 1 is the default subband used by
the pointing solver.  Now, why antsol was not happy is the next
question; perhaps it is related to the problems Rick reported
in the third part of his report.