[alma-config]misc config comments

[mel wright 456]

I don't think large array configs need to have short spacings.
Some overlap in spatial frequencies for multiple configuration
cross calibrations is good, but no need to overdo it. One
could make joint observations with ACA if there is a case for
short and long at the same epoch.

> on average, positive sidelobes over some (inner) region of the PSF

- looks very like the large scale error beam which has plagued many
single dish observations. If there is a lot of power in unsampled
uv points (like those missing, or inaccuarate short spacings),
then expect trouble.


Frederic statement looks OK to me.

> Thus, in interferometry, a given distribution of
> Fourier samples yielding high sidelobes may allow to
> reconstruct the brightness distribution with high
> precision provided that the uv-plane is sampled with 
> the required accuracy.

Not necesarily true, as Mark says.  The bounding box
is a good example of algorithms taking advantage of
knowledge of the completeness of the (u,v). Formally,
one could convolve the uv-data by the FT of the bounding box
and have completely sampled uv-data for that source.

My 2 cents.

Cheers, Melvyn