[alma-config]Re: [alma-site]Reconfiguration Times

[mel wright 456]

Hi Mark,

w.r.t..
2) I am somewhat concerned about the accuracy of baseline and pointing
   determinations from the subarray of just 3 antennas that have
   just been reconfigured.  Has anyone done the numbers on this, or
   thought of this?

I did think about this. It would be good to include a number of unmoved
antennas in the baseline and pointing determination to improve the SNR,
but more importantly to determine the antenna positions w.r.t. the rest
of the
array.

At Hat Creek we noticed error propagation if the selection of unmoved,
reference
antennas changes. In practice we use the whole array for each baseline
solution.

If there were some "fixed" ALMA antennas (for compact array, or single
dish)
these could be the reference antennas, but might be on long baselines to
the
moved antennas. I imagine a satisfactory baseline fitting procedure will
evolve after some experience on site.


best wishes,

Melvyn.