Specifying antenna/station positions and diameters

Picking an ALMA configuration

This plot gives a quick estimate of the beam size for a zenith-transiting source. The X axis is configuration number e.g. "almaconfig.out20":
beamsummary.png CASA <10> repodir=os.getenv("AIPSPATH").split(' ')[0]+"/data/alma/simmos/"
CASA <11> antennalist=repodir+"almaconfig.out20"

If you prefer to just download the text files, here they are:
  • for OLD CASA / almasimmos (v2.3, release before June 2009): almaconfigs.tgz
  • for NEW CASA / simdata (v2.4 ~June 2009 or alpha prerelease from remy) configs.tgz

suggestalmaconfig.py will recommend a configuration given a desired resolution, frequency, and source declination. It doesn't know about the ACA yet, so if it recommends O-01 you should consider manually picking an ACA configuration. You will also need these data files of beam summary tables:beamsummaries.tar.gz

File format

simdata reads the antenna positions from an ASCII file with four columns: X,Y,Z, and diameter. For example for ALMA,

  1. UTM-X (Easting; meters).
  2. UTM-Y (Northing; meters).
  3. Z (Altitude in meters)
  4. Diameter (meters). simdata uses a primary beam calculated using Airy patterns for the diameters you specify and a 1m diameter circular blockage in the center of each antenna or station.

Comments and headerl lines start with a #
You can specify several coordinate systems, using the comment lines as "headers" e.g.
# observatory = VLA
# coordsys = XYZ
and then input coordinates in X,Y,Z earth-centered ITRF.

You must specify observatory and coordsys in the header. See configs.tgz for examples (ALMA, EVLA, SMA, CARMA, etc)

email rindebet at nrao.edu if you have questions.
Topic attachments
I Attachment Action Size Date Who Comment
beamsummaries.tar.gzgz beamsummaries.tar.gz manage 8.3 K 2009-01-29 - 15:40 RemyIndebetouw beam summary tables
beamsummary.pngpng beamsummary.png manage 24.6 K 2009-01-30 - 08:40 RemyIndebetouw  
configs.tgztgz configs.tgz manage 7.1 K 2009-05-20 - 10:44 RemyIndebetouw configuration files
Topic revision: r5 - 2009-05-20, RemyIndebetouw

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