Evaluation of the ALMA Prototype Antennas
Abstract
The ALMA (Atacama Large Millimeter Array) North American and European prototype antennas have been evaluated by a variety of measurement systems to quantify the major performance specifications. Near-field holography was used to set the reflector surfaces to 17 μm rms. Pointing and fast-switching performance was determined with an optical telescope and by millimeter-wavelength radiometry, yielding 2" absolute and 0.6" offset pointing accuracies. Path-length stability was measured to be <~20 μm over 10 minute time periods using optical measurement devices. Dynamical performance was studied with a set of accelerometers, providing data on wind-induced tracking errors and structural deformation. Considering all measurements made during this evaluation, both prototype antennas meet the major ALMA antenna performance specifications.
The performance results presented in this publication were part of a comprehensive technical evaluation process used to evaluate the ALMA prototype antennas, which concluded in 2005 April.- Publication:
-
Publications of the Astronomical Society of the Pacific
- Pub Date:
- September 2006
- DOI:
- 10.1086/508298
- arXiv:
- arXiv:astro-ph/0609329
- Bibcode:
- 2006PASP..118.1257M
- Keywords:
-
- Telescopes;
- Instrumentation: Interferometers;
- Astrophysics
- E-Print:
- 83 pages, 36 figures, AASTex format, to appear in PASP September 2006 issue