[mmaimcal] ACA Antenna Specs

[Al Wootten]

Hi Mark

In my understanding interpolation is the plan, for the atmosphere from the
WVRs on the 12ms and the instrumental part will have to be guesstimated from 
phase calibrator observations.  During these, of course, the 7m can benefit
by the many more antennas to which they will have baselines.

In fact, the joint correlated observation mode still needs a change request,
to go past the change committee and through the Director.  During this
process we need to address questions of exactly this ilk.  As a result of the
process, we'll come to understand better the full cost of the 'upgrade' of
which software additions will be a component.  As we noted yesterday, so will
the lower efficiency as the array waits for the 7m upon slewing to a source.
But Tetsuo notes the higher efficiency in terms of 7m calibration offsets this.

This all needs careful thought.

Clear skies,
Al
Mark Holdaway writes:
 > Al,
 > 
 > If "ACA does not fast switch", what is the phase calibration strategy for
 > when we do joint correlated observations?  Will the ACA's 4 large dishes
 > phase solutions be spatially interpolated for teh ACA antennas?
 > If so, more software.
 >  
 >     -Mark
 > 
 > 
 > 
 > Al Wootten wrote:
 > 
 > >Folks,
 > >
 > >Yesterday we discussed the science implications of changes proposed for the ACA 
 > >7m antenna specifications and requirements.  I tried to summarize these.
 > >In the spaces of today's LPR and LLC discussions I spoke about these with
 > >Tetsuo.  On the basis of our chat, I think I understand the reasons for some
 > >of these changes.  In principle, I think it is not good to have many different
 > >versions of antenna specifications and requirements.  But ALMA is a project of
 > >practicalities, not principles.
 > >
 > >I added some further words to the discussion document at:
 > >http://www.cv.nrao.edu/~awootten/mmaimcal/ACASpecReqsDiffs.txt
 > >Please comment.
 > >
 > >Clear skies,
 > >Al
 > >+--------------------------------------------------------+
 > >| Alwyn  Wootten   (http://www.cv.nrao.edu/~awootten/)	 |
 > >| Project Scientist, Atacama Large Millimeter Array/US   |
 > >| Astronomer, National Radio Astronomy Observatory       |        
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 >