[mmaimcal]comments on Y+ vs. ring configuration notes from stephane

[Stephane Guilloteau]

> > B) Better astrometric performance
> >
    I had  a subtle argument in mind when saying so. That argument may be
wrong. Here it is:
The advantage of the ring array for astrometry is not resolution. It is he
accuracy of the delay determination.
This accuracy is better than for an equivalent (in terms of angular
resolution) Y+ array, because in the ring
any antenna has essentially the same number of short baselines than of the
longest baselines. The antenna
phase being determined using all baselines, this may give a small advantage
to the ring...

    Quantitatively, it may be peanuts...

    Any comment ?

    Stephane