[mmaimcal] Nutators

[Jeff Mangum]

Hi Peter,

Basing an important decision like the need for nutators on the ALMA
antennae on an unfinished memo is dangerous.  I have recently been
looking over this memo (trying to decipher it, actually) and find that
there appear to be some conclusions which are in conflict with our
experience with the 12m system.  Fast motion might be the saviour, but
it is unproven.  Real measurements must be made to support any
decision made on this issue.

"Peter" == Peter Napier <pnapier at nrao.edu> writes:

Peter> With respect to Al's comment that he thinks choppers may be needed.
Peter> So that everyone knows what the current baseline plan is with respect to
Peter> subreflector nutators, the assumption within the antenna group at
Peter> present is that antenna fast motion will do what is needed (see
Peter> unpublished Holdaway memo) and so nutators are NOT budgeted for the
Peter> production antennas. The test antennas will have a nutator and the
Peter> production antennas will have a spacer where a nutator could be
Peter> inserted.
Peter> -- 
Peter> Peter Napier
Peter> NRAO
Peter> PO Box 0, Socorro, NM 87801
Peter> Ph 505 8357218, Fax 505 8357027