[mmaimcal] Munich

[Steven T. Myers]

On Tue, 29 Feb 2000, Bryan Butler wrote:

> >It is not clear to me why there needs to be some (small) hard limit to
> >subarrays such as 4 - is there a good explanation on how they are
> >implemented?
> 
> i agree, but d'addario had argued very strongly to limit the number
> of possible subarrays.  we went over and over this, with the scientists
> saying it wasn't enough, and larry saying the number had to be explicitly
> defended, and us defending the number, and larry saying it cost too
> much, etc...  this may have been before you got here, steve.  i thought
> we had convinced larry that we needed *at least* 5, and possibly more,
> though?  4 seems awfully restrictive to me.

It is clear we had better come up with some compelling examples of
subarray modes with more than 4 subarrays.  I would guess that right off
the top, there will likely be 4 subarrays in use:

#1 - antennas out for reconfiguring (and baselines)
#2 - antenna(s) out for VLBI
#3 - main interferometric observing array
#4 - single dish subarray

which leaves NO ROOM for anything more!  For example, I could see more
than 1 single dish subarray and more than 1 interferometric subarray 
for example

#5 - second interferometric subarray (transient object monitoring, eg.
GRB)

Any thoughts on this?  I would think this sort of example would be
compelling, and that 8 subarrays would be more reasonable.

> >It seems ludicrous to use one antenna in single-dish mode.  Why would you
> >add in single-dish data with much worse noise level if your desire is
> >to actually improve the images?  My guess (purely a guess) is something
> >like sqrt(N) = 8 for N=64 antennas is the minimum...
> 
> i don't know about 8 being the limit, but i agree that 1 is *way*
> too small.  how does stephane think that the data from only 1 antenna
> will be used?  if you only have 5 antennas in your array (ala IRAM
> or OVRO), then adding in data from 1 dish *might* make sense.  if you
> have 64 antennas, it makes no sense (to me at least).

I guess we should work out the sensitivity numbers...

  -steve