[asac][almanews] ALMA Memos 419 Released

[Stacy Oliver]

ALMA MEMO #419

THE Y+ LONG-BASELINE CONFIGURATION TO ACHIEVE HIGH RESOLUTION WITH ALMA

Angel Otárola (ESO) & Mark A. Holdaway (NRAO)

04/12/2002

Keywords: Y+, configuration, resolution, roads, pads

The ALMA array configuration design has been split into a compact array, an
extended array, and a “zoom” spiral array which aims to connect them.  The
currently accepted extended array is a 14 km ring around Chascón.  Based on
Fourier plane coverage, resolution, operations, engineering, and
environmental arguments, we present an alternative to the extended
configuration: a Y-shaped set of zooming configurations, which naturaly
grows out of the spiral zoom configurations.  This set of preliminary
configurations indicates a savings of about 20 km in roads and cables, and
35 fewer pads compared to the current ring design.  It has smoothly varying
resolution, which permits the observer to tailor the resolution to his
requirements. Reconfiguration is much smoother with the Y configuration than
the 14 km diameter ring.  The most extended Y configuration obtains the same
resolution as the 14 km ring array. However, in order to achieve these
advantages, together with the highest possible resolution for the ALMA
interferometer, we need to explore the possibility of extending the Science
Preserve by at least two kilometres to the west of its current western
boundary.


View a pdf version of ALMA Memo #419.
http://www.alma.nrao.edu/memos/html-memos/alma419/memo419.pdf

Download a postscript version of ALMA Memo #419.
http://www.alma.nrao.edu/memos/html-memos/alma419/memo419.ps

Download a zipped postscript version of ALMA Memo #419.
http://www.alma.nrao.edu/memos/html-memos/alma419/memo419.zip

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