[daip] Test Session on June 4

[Eric Greisen]

Data Analysts writes:

 > I have looked at the data tape you sent from my test run on June 4. Thanks
 > for getting it to me so quickly. I think I understand the numbers on it,
 > but I thought I would make a couple of inquiries to make sure. I ran FILLM
 > and generated a data base for the three antennas in my array. The point of
 > this test was to measure the system temperatures as we pointed closer and
 > closer to the Sun. After creating the data base, I ran LISTR with
 > DPARM(1)=10, which is advertised as giving the system temperatures. The
 > numbers I get appear to be *proportional to * the system temperature, but
 > not the system temperature itself. For example, for a pointing far from
 > the Sun I get a number of about 190, where I would expect 50. The scale on
 > the printout says 1000=1.0 Kelvin, which makes absolutely no sense.
 > As long as these numbers are indeed proportional to the system
 > temperature, I can work with them, and indeed have already done so. I
 > suspect there is something funky about the normalization or conversion
 > number to true system temperatures. However, to be absolutely sure, I
 > thought I would talk to some experts and make sure I was not studying the
 > power settings on the array operators' microwave ovens. Any input you
 > could give would be helpful.

I forgot that LISTR would display something from the TY table - I
always use SNPLT and PRTAB.  The VLA gives us only one "temperature"
in two forms, separated by a single scaling factor which I think is
the same for all antennas.  The temperature in something like degrees
appears in one of the columns (Tant) while the number used to scale
the data to deci-Jy has been stored in the "Tsys" column (values
around 0.2 or so).  Neither of these are calibrated Tsys values - the
calibrations can be quite far off with an antenna-dependent error -
but they are proportional to the system temperature.  If they were
correctly calibrated, then we would not need the amplitude part of
CALIB.

Eric Greisen