[mmaimcal]Memo 428

[mel wright 456]

Hello John,

RE:
 The 15m minimum distance is the spec for antennas not to
interact mechanically  if pointing in arbitary directions.
If we really were not going to have the ACA then one might
I guess consider relaxing this spec and have a few be closer
to each other and somehow ensure that are slaved to point in
the same direction (but if one antenna fails all then cannot
move). But with 4 million dollar antennas we don't want any
risks I guess.

- -> In the BIMA compact arrays,  the antennas are within colliding
distance.  We do exactly as you suggest;  anti-collision
software  and hardware  protect against collisions. The biggest problem
is false collisions when snow or birds trip the anti-collision hardware.

This concept does not seem to be popular at any other observatory !


cheers,

Melvyn

PS .  what is the nominal longitude, latitude and height of the center
for the  compact alma array. ?