[alma-config] My HP address and etc.

[Min S. Yun]

I suspect Morita-san's comment on the short spacing should be
interpreted only in the sense of understanding the imaging
defects in the existing simulations.  With a finite number of
antennas, we are always forced to make trade-offs, and the
trade-offs made in the current double-ring/donut array is
preserving the self-similarity.  My own thinking in not allowing
for more short baselines for the "A" and "B" arrays is that
given the limited number of antennas available, the hole in
the uv-coverage is best covered by multi-configuration 
observations rather than arbitrarily foregoing the underlying
design concept.  This is the same idea as Leonia's point
that you have to trade off resolution and uv-coverage.
I would like to remind people that you have to keep in mind
some of these fundamental differences between these and
Conway designs when comparing their imaging performance.
We can always debate the merit of filling the central hole
in the uv-coverage by adding snapshot data from the compact
configuration (ACA?).  I happened to believe that devoting
a small number of antennas to stretch the spatial dynamic
range of an array is a poor solution.


				-- Min


On Wed, 3 Jan 2001, [Leonia Kogan] wrote:

> Comment about short spacing-angular resolution
> 
> Of cource the short spacing argument is very important.
> But selecting configuration with good short spacing coverage we are 
> coming to a center condencing UV coverage which gives a wider sinthesize beam.
> 
> So improving short spacing coverage we are loosing in angular resolution.
> The minimum spacings of A array and B array of Min and Kogan's straw person 
> plan may be too large but on the other hand the angular resolution 
> of these arrays should be better than a center condensed configuration.
> 
> Leonia
> 
> 
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> >From owner-alma-config at kochab.cv.nrao.edu Wed Jan  3 10:04 MST 2001
> Date: Thu, 04 Jan 2001 01:59:37 +0900
> From: "Morita, Koh-Ichiro" <morita at nro.nao.ac.jp>
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> Subject: [alma-config] My HP address and etc.
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> 
> Dear all,
> 
> A happy new year.
> 
> My HP address:
> I have come back to Nobeyama from Tucson.
> So, my site in NRAO tucson will be closed soon.
> If you want to see my report about ACA, please contact at
> http://www.nro.nao.ac.jp/~morita/CONFIG/aca_study.html
> 
> Comment about the short spacing:
> I strongly agree with Mark's argument about short spacing problem 
> in his email on 12/19.  Short spacing coverage is very important
> for higher resolution observations.  For compact sources in star
> forming regions, we should measure visibilities at very short 
> baselines to avoid the effect from compact structures within
> the primary beam.  So, I think, the minimum spacings of A array and 
> B array of Min and Kogan's straw person plan are too large.
> 
> Koh-Ichiro
> ----------------
> 
> Koh-Ichiro Morita
> Nobeyama Radio Observatory
> National Astronomical Observatory,
> 
> Minamimaki, Minamisaku, 
> Nagano 384-1305, Japan
> Email morita at nro.nao.ac.jp
> 
> 
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