[mmaimcal]Early science Configs

[John Conway]

Hi,

 Mark makes some good points, I agree a spatial dynamic range of 20
is hard for 6 antennas. but for a fully 1D array of 6 antennas close to
EW then  a baseline range of 20 could just about be achieved, but long
tracks  are then of course required to get good azimuthal coverage.

Its more in line with the pad pattern and expandability of the array to
full operation to have a 2D pattern of 6 antennas. For instance an outer
triangle of three antennas and an inner triangle,will give azimuthally good
uv covergae in 3-6hrs , but has a low spatial dynamic  range (like 3-5 maybe),
however by combining two such arrays one  could get a  useful array for
astronomical imaging,

      Jihn


On Wed, 14 Jan 2004, Mark Holdaway wrote:

>
> I think that these are reasonable boundary conditions (though a factor
> of 20 between long and short baselines for 6 antennas seems to be
> stretching it -- the VLA, with 27 antennas, has a ratio of 40), but
> I think the defining concepts for this task may be:
>
> (1) that we usually want to use multiple configurations to get good (u,v)
> coverage (this is ALMA, not OVRO).
>
> (2) that we want these configurations to be "expandable" in that
> we will be adding antennas every month or so.  I know this was not
> part of the current objective, but that is really the ultimate task.
> Initially (ie, when there are 6 antennas), we may move all or almost
> all between each configuration -- but at some point, more and more
> antennas will NOT be moved as we change configurations.
>
>    -Mark
>