[mmaimcal] Re: [alma-sw-ssr] question about frequency/band switching speeds and rates

[Ed Fomalont]

Hello all,

1.  Discrete changing of the phasing while doing an OTF is okay, as
long as the phase change for a source in the beam doesn't change by
more than about 10 deg between phase center updates - whatever
time increment this is for the highest frequency and longest baseline.

2.  I worry about the true pointing (ie. encoder values) of the
antennas during an OTF observation.  For a single dish OTF, the basic
data is RA, DEC pointing and Intensity.  In the SDM for arrays, the
antenna pointing (actual encoder value, not commanded value) is probably
buried somewhat deeply in the data collection.  Is this a problem?
For example, if an antenna position is more than xx away from the mean
position of the other antennas, perhaps it should be flagged.  The ATCA
has been doing OTF observations - they might have some guidance.

Ed