The OVRO 40 meter Telescope is a

radio telescope A radio telescope is a specialized antenna (radio), antenna and radio receiver used to detect radio waves from astronomical radio sources in the sky. Radio telescopes are the main observing instrument used in radio astronomy, which studies the r ...

at the

Owens Valley Radio Observatory Owens Valley Radio Observatory (OVRO) is a radio astronomy observatory located near Big Pine, California (US) in Owens Valley. It lies east of the Sierra Nevada, approximately north of Los Angeles and southeast of Bishop. It was established in 19 ...

near

Big Pine, California Big Pine (formerly Bigpine) is a census-designated place (CDP) in Inyo County, California, United States. Big Pine is located approximately south-southeast of Bishop. Its population was 1,875 at the 2020 census, up from 1,756 at the 2010 census. ...

, US. It is owned and operated by

Caltech The California Institute of Technology (branded as Caltech) is a private university, private research university in Pasadena, California, United States. The university is responsible for many modern scientific advancements and is among a small g ...

. The telescope is easily visible from the section of

US highway 395 U.S. Route 395 (US 395), also known as U.S. Highway 395, is a north–south United States Numbered Highway that traverses the inland areas of the western states of California, Nevada, Oregon, and Washington. It travels for over from a junction ...

just north of Big Pine.

History

Construction of the telescope was funded by the

National Science Foundation The U.S. National Science Foundation (NSF) is an Independent agencies of the United States government#Examples of independent agencies, independent agency of the Federal government of the United States, United States federal government that su ...

, as a prototype for a planned

astronomical interferometer An astronomical interferometer or telescope array is a set of separate telescopes, mirror segments, or radio telescope antennas that work together as a single telescope to provide higher resolution images of astronomical objects such as stars, n ...

at Owens Valley. The interferometer was to incorporate eight dishes moving on

rails Rail or rails may refer to: Rail transport *Rail transport and related matters * Railway track or railway lines, the running surface of a railway Arts and media Film * ''Rails'' (film), a 1929 Italian film by Mario Camerini * ''Rail'' (1967 fi ...

, positioned up to apart. The 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 The Karl G. Jansky Very Large Array (VLA) is a centimeter-wavelength radio astronomy observatory in the southwestern United States built in the 1970s. It lies in central New Mexico on the Plains of San Agustin, between the towns of Magdalena, Ne ...

. The newly-constructed prototype was instead combined with existing telescopes at Owens Valley to form a smaller interferometer, with maximum baseline of . Starting in 1969, it was also sometimes used as a

very long baseline interferometry Very-long-baseline interferometry (VLBI) is a type of astronomical interferometry used in radio astronomy. In VLBI a signal from an astronomical radio source, such as a quasar, is collected at multiple radio telescopes on Earth or in space. T ...

(VLBI) station, in conjunction with more distant observatories. When operating with the

Parkes telescope Parkes Observatory is a radio astronomy observatory, located north of the town of Parkes, New South Wales, Australia. It hosts Murriyang, the 64 m CSIRO Parkes Radio Telescope also known as "The Dish", along with two smaller radio telescopes. T ...

Australia Australia, officially the Commonwealth of Australia, is a country comprising mainland Australia, the mainland of the Australia (continent), Australian continent, the island of Tasmania and list of islands of Australia, numerous smaller isl ...

it provided the longest baseline then available in the world, and hence the highest

angular resolution Angular resolution describes the ability of any image-forming device such as an Optical telescope, optical or radio telescope, a microscope, a camera, or an Human eye, eye, to distinguish small details of an object, thereby making it a major det ...

of 0.4

milliarcseconds A minute of arc, arcminute (abbreviated as arcmin), arc minute, or minute arc, denoted by the symbol , is a unit of angular measurement equal to of a degree. Since one degree is of a turn, or complete rotation, one arcminute is of a tu ...

. VLBI operations continued until 1991, when they were retired in favour of the more capable

Very Long Baseline Array The Very Long Baseline Array (VLBA) is a system of ten radio telescopes which are operated remotely from their Array Operations Center located in Socorro, New Mexico, as a part of the National Radio Astronomy Observatory (NRAO). These ten radio ...

Current use

In 2007 the telescope was re-purposed for a dedicated

blazar A blazar is an active galactic nucleus (AGN) with a relativistic jet (a jet composed of ionized matter traveling at nearly the speed of light) directed very nearly towards an observer. Relativistic beaming of electromagnetic radiation from the ...

monitoring campaign, in support of the

Fermi Gamma-ray Space Telescope The Fermi Gamma-ray Space Telescope (FGST, also FGRST), formerly called the Gamma-ray Large Area Space Telescope (GLAST), is a space observatory being used to perform gamma-ray astronomy observations from low Earth orbit. Its main instrument is ...

which launched in 2008 and observes blazars in

gamma ray A gamma ray, also known as gamma radiation (symbol ), is a penetrating form of electromagnetic radiation arising from high energy interactions like the radioactive decay of atomic nuclei or astronomical events like solar flares. It consists o ...

s. the telescope takes regular measurements of over 1800 blazars, by observing each one at twice a week.

In popular culture

Much of the 1996 film ''The Arrival'' was filmed at Owens Valley Radio Observatory, and the climactic fight scene occurred in, and on the primary mirror of, the 40 meter telescope.

References

External links

The Owens Valley Radio Observatory

The OVRO 40M Telescope Fermi Blazar Monitoring Program
{{Portal bar, California, Astronomy, Stars, Outer space, Solar System, Education, Science Radio telescopes Astronomical observatories in California Buildings and structures in Inyo County, California

History

Current use

In popular culture

See also

References

External links