[evlatests] Adventures from last night

[Rick Perley]

    The 9.5 hour observation of Herc-A taken last night was not a major 
success.  Many odd things occurred. 

    1) The most obvious failure is a nearly 4-hour gap in the archive, 
from 12:56 IAT through 16:37 IAT. 

    2) A more subtle problem is the lack of visibility data from both 
polarization calibrators, 3C286 and J1504+1029.  Observations of these 
sources required moderate to large slews.  It is clear after careful 
examination that the system greatly underestimated slew times.  I 
utilized the 'on source' timing in the OPT -- this worked beautifully 
for the massive 'flux densities' run, but has failed in the Herc A run.  
In general, since I used a loop through the bands such that S-band was 
always observed last, I did get S-band data for most of the polarization 
calibration attempts. 

    3) There are blocks of missing scans.  The first occurred on the 
initial observation of 3C286 -- the L and X band observations are 
present, but the following observations at C-band and S-band are 
completely missing (and there is a 3 minute time gap corresponding to 
where  the data should have been).  Data flowed again on the following 
L-band scan.  The IAT times for this gap are 07:52:22 through 07:55:33 ( 
00:52 through 00:55 in local time). 
    Later on, a much larger gap -- 10 minutes occurred, again following 
a X-band observation (when the next observation would be at C-band).   
The time range here was 09:02:17 to 09:12:48.