OVRO 40 meter Telescope

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OVRO 40 meter Telescope
OVRO 40m telescope 01.jpg
ObservatoryOwens Valley Radio Observatory Edit this on Wikidata
Location(s)California, US
Coordinates37°14′00″N 118°17′02″W / 37.2333°N 118.284°W / 37.2333; -118.284Coordinates: 37°14′00″N 118°17′02″W / 37.2333°N 118.284°W / 37.2333; -118.284 Edit this at Wikidata
OrganizationCalifornia Institute of Technology Edit this on Wikidata
First light1968 Edit this on Wikidata
Diameter40 m (131 ft 3 in) Edit this at Wikidata
Websitewww.ovro.caltech.edu Edit this at Wikidata
OVRO 40 meter Telescope is located in the United States
OVRO 40 meter Telescope
Location of OVRO 40 meter Telescope

The OVRO 40 meter Telescope is a radio telescope at the Owens Valley Radio Observatory near Big Pine, California, US. It is owned and operated by Caltech.


Construction of the telescope was funded by the National Science Foundation, as a prototype for a planned astronomical interferometer at Owens Valley.[1] The interferometer was to incorporate eight dishes moving on rails, positioned up to 5 miles (8.0 km) apart.[1] The 40-metre (130 ft) diameter prototype was completed in 1968, but by the end of the decade plans for the interferometer were cancelled in favour of the Very Large Array.[1]

The newly-constructed prototype was instead combined with existing telescopes at Owens Valley to form a smaller interferometer, with maximum baseline of 0.75 miles (1.21 km).[1] Starting in 1969, it was also sometimes used as a very long baseline interferometry (VLBI) station, in conjunction with more distant observatories.[1] When operating with the Parkes telescope in Australia it provided the longest baseline then available in the world, and hence the highest angular resolution of 0.4 milliarcseconds.[1] VLBI operations continued until 1991, when they were retired in favour of the more capable Very Long Baseline Array.[1]

Current use[edit]

In 2007 the telescope was re-purposed for a dedicated blazar monitoring campaign, in support of the Fermi Space Telescope which launched in 2008 and observes blazars in gamma rays. As of 2018 the telescope takes regular measurements of over 1800 blazars, by observing each one at 15 gigahertz (2.0 cm) twice a week.[2]


  1. ^ a b c d e f g "History". Owens Valley Radio Observatory. Caltech. Retrieved 23 July 2018.
  2. ^ "Monitoring of Fermi Blazars". OVRO 40m Telescope. Caltech. Retrieved 23 July 2018.