[mmaimcal] SMA as the ACA

[Al Wootten]

Well, it happened.

It has been proposed that when ALMA reaches completion ~2010, the SMA might
be moved to Chajnantor to serve as the ACA (which would, in this case,
not be built).

We could enumerate the problems this would entail from different optics
concepts (SMA operates two bands simultaneously) and on.  But we should
anticipate discussions about this.  Political problems are for others to
decide.  Operational problems we could list.  But scientific problems
should be our priority--if any ACA will improve ALMA's capabilities
can the SMA fill the bill.

Some Specs, from Mark Gurwell:
8 x 6m antennas             partners: Smithsonian plus Taiwan
surface 13 microns measured on one at least, and apparently stable
pointing 1" but not quite there yet
secondary 350mm;            feed legs not off edge of antenna
may not be easy to accommodate freqs below 2mm.

The money providers will see this as a free ACA and there will be tremendous
pressure to use it for that.  We need to determine if it is what ALMA
needs and to bolster that case scientifically.

I feel that since the subject has been broached we should include this in
the range of ACA options that the tiger team will simulate.  I asked
Gurwell to consider talking about this at the ASAC meeting in Santiago,
should Ewine-Geoff-Yasuo feel it is appropriate.

Comments??

Clear skies,
Al