[asac] [almanews] ALMA Memos Released

[Carolyn White]

ALMA Memo #334 - Revision 1

Refined Position of ALMA Equipment on Chajnantor, Mauna Kea, and the South Pole 

Simon J. E. Radford and Richard A. Chamberlin

December 2000

Measurements of the 225 GHz atmospheric transparency with functionally
identical tipping radiometers at Mauna Kea, the South Pole, and Chajnantor
indicate periods of excellent observing conditions at all three
sites. Conditions at Chajnantor and the South Pole are better than at
Mauna Kea. The first quartile zenith transparency at Chajnantor and the
South Pole are roughly equal. During the best conditions at Chajnantor,
however, the zenith transparency is better than during the best conditions
at the South Pole.

View a PDF version of ALMA Memo #334 - Revision 1.
     http://www.alma.nrao.edu/memos/html-memos/alma334/memo334-1.pdf

Download a postscript version of ALMA Memo #334 - Revision 1.
     http://www.alma.nrao.edu/memos/html-memos/alma334/memo334.ps

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ALMA Memo #338

The Best Sites for the Compact ALMA Configuration

Bryan Butler, Simon Radford, and Angel Otarola

December 2000

We present considerations involved in finding the best location for the
compact (maximum antenna separation <~ 200 m) ALMA configuration on the
science preserve. Several candidate locations for the compact
configuration are then suggested. Note that we distinguish here between
the compact ALMA configuration and the so-called ``Atacama Compact Array''
(or ACA) which is a separate collection of smaller antennas. We do not
consider the placement of the ACA in this memo.

Download a PDF version (9 MB) of ALMA Memo #338
     http://www.alma.nrao.edu/memos/html-memos/alma338/memo338.pdf

Download a postscript version (16 MB) of ALMA Memo #338
     http://www.alma.nrao.edu/memos/html-memos/alma338/memo338.ps

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ALMA Memo #339

Aspects of the Antennas for the ALMA Compact Array (ACA) 

Jacob W.M. Baars

The Atacama Compact Array (ACA) will supplement ALMA in order to provide
the "missing spacings" in the uv-plane coverage, caused by the finite size
of and the minimum distance between the elements of ALMA. ACA will
consists of about a dozen small antennas of a diameter between 6 and 8
m. In this Memo I consider a number of aspects related to the
antennas. After reviewing the basic requirements on the antennas, I look
in some detail on the possibilities of using the ALMA antenna mounting for
the ACA dishes.  Minimizing the "collision radius" to enable close packing
is important for the ACA. I suggest a straw man ACA antenna consisting of
a 7 m diameter reflector with a short focal length (F/D = 0.3) on an ALMA
mounting. A number of points for further study is listed.

Download a PDF version (9 MB) of ALMA Memo #339
     http://www.alma.nrao.edu/memos/html-memos/alma339/memo339.pdf

Download a postscript version (16 MB) of ALMA Memo #339
     http://www.alma.nrao.edu/memos/html-memos/alma339/memo339.ps

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