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Applied Optics

Applied Optics


  • Editor: Joseph N. Mait
  • Vol. 51, Iss. 3 — Jan. 20, 2012
  • pp: 316–322

Millimeter-wave center of curvature test for a fast paraboloid

Samuel Goldberg and Stephen Padin  »View Author Affiliations

Applied Optics, Vol. 51, Issue 3, pp. 316-322 (2012)

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We describe a technique for measuring the surface profile of a radio telescope with a fast paraboloidal primary. The technique uses a sensor, at the center of curvature of the primary, consisting of a millimeter-wave source and an array of receivers to measure the field in the caustic. The sensor is mounted on the telescope enclosure and it moves with the telescope, so the measurements can be used for continuous, slow, closed-loop control of the surface. Sensor decenter and despace errors, due to wind buffeting and thermal deformation of the sensor support, do not compromise the surface measurements because they result in profile errors that are mainly translation, which has no effect on astronomical observations, or tilt and defocus, which can be measured using astronomical sources. If the position of the sensor is known to 20 μm rms, the surface can be measured to 1μmrms at λ=3mm.

© 2012 Optical Society of America

OCIS Codes
(090.2910) Holography : Holography, microwave
(110.6770) Imaging systems : Telescopes
(120.6650) Instrumentation, measurement, and metrology : Surface measurements, figure
(350.1260) Other areas of optics : Astronomical optics

ToC Category:
Instrumentation, Measurement, and Metrology

Original Manuscript: July 5, 2011
Manuscript Accepted: September 11, 2011
Published: January 16, 2012

Samuel Goldberg and Stephen Padin, "Millimeter-wave center of curvature test for a fast paraboloid," Appl. Opt. 51, 316-322 (2012)

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