The Westerbork Synthesis Radio Telescope (WSRT) is an

aperture synthesis Aperture synthesis or synthesis imaging is a type of interferometry that mixes signals from a collection of telescopes to produce images having the same angular resolution as an instrument the size of the entire collection. At each separation and ...

interferometer Interferometry is a technique which uses the '' interference'' of superimposed waves to extract information. Interferometry typically uses electromagnetic waves and is an important investigative technique in the fields of astronomy, fiber o ...

built on the site of the former World War II Nazi detention and transit camp Westerbork, north of the village of Westerbork,

Midden-Drenthe Midden-Drenthe () is a municipality in the northeastern Netherlands. The municipality was created in 1998, in a merger of the former municipalities of Beilen, Smilde, and Westerbork. Between 1998 and 2000, the name of the municipality was Midden ...

, in the northeastern

Netherlands ) , anthem = ( en, "William of Nassau") , image_map = , map_caption = , subdivision_type = Sovereign state , subdivision_name = Kingdom of the Netherlands , established_title = Before independence , established_date = Spanish Netherl ...

Overview

The WRST comprises fourteen 25-metre radio telescopes deployed in a linear array arranged on a East-West line, of which 10 are in a fixed equidistant position, 2 are nearby on a 300 m rail track, and 2 are located a kilometer eastwards on another 200 m rail track. It has a similar arrangement to other radio telescopes such as the One-Mile Telescope,

Australia Telescope Compact Array The Australia Telescope Compact Array (ATCA) is a radio telescope operated by CSIRO at the Paul Wild Observatory, twenty five kilometres (16 mi) west of the town of Narrabri in New South Wales, Australia. Its opening ceremony took place on ...

and the Ryle Telescope. Its

Equatorial mount An equatorial mount is a mount for instruments that compensates for Earth's rotation by having one rotational axis, the polar axis, parallel to the Earth's axis of rotation. This type of mount is used for astronomical telescopes and cameras. Th ...

is what sets it apart from most other radio telescopes, most of which have an

Altazimuth mount An altazimuth mount or alt-azimuth mount is a simple two- axis mount for supporting and rotating an instrument about two perpendicular axes – one vertical and the other horizontal. Rotation about the vertical axis varies the azimuth (compass b ...

. This makes it specifically useful for specific types of science, like polarized emission research as the detectors maintain a constant orientation on the sky during an observation. Ten of the telescopes are on fixed mountings while the remaining two dishes are movable along two

rail tracks A railway track (British English and UIC terminology) or railroad track (American English), also known as permanent way or simply track, is the structure on a railway or railroad consisting of the rails, fasteners, railroad ties (sleepe ...

. The telescope was completed in 1970 and underwent a major upgrade between 19952000. The telescopes in the array can operate at several frequencies between and with an instantaneous bandwidth of and 8092line spectral resolution. The WSRT is often combined with other telescopes around the world to perform very-long-baseline interferometry (VLBI) observations, being part of the

European VLBI Network The European VLBI Network (EVN) is a network of radio telescopes located primarily in Europe and Asia, with additional antennas in South Africa and Puerto Rico, which performs very high angular resolution observations of cosmic radio sources usin ...

. The telescope is operated by

ASTRON Astron may refer to: * Mitsubishi Astron engine * ASTRON, the Dutch foundation for astronomy research, operating the Westerbork Synthesis Radio Telescope and LOFAR * Astron (comics), a fictional character, a member of the Marvel Comics group The ...

, the Netherlands Institute for Radio Astronomy. WSRT performed a major upgrade in 2013 as part of the APERTIF (APERture Tile In Focus) project, where the current detectors were replaced with focal-plane arrays. The Telescope was out of operation for the upgrade from 2015 to 2019, which allows a 25x larger field of view. The upgraded telescope is used for large scale surveys of the northern sky, bringing back focus on the

Hydrogen line The hydrogen line, 21 centimeter line, or H I line is the electromagnetic radiation spectral line that is created by a change in the energy state of neutral hydrogen atoms. This electromagnetic radiation has a precise frequency of , w ...

for which it was originally designed, but also large

pulsar A pulsar (from ''pulsating radio source'') is a highly magnetized rotating neutron star that emits beams of electromagnetic radiation out of its magnetic poles. This radiation can be observed only when a beam of emission is pointing toward E ...

searches and other science. The WSRT is also an International

GNSS A satellite navigation or satnav system is a system that uses satellites to provide autonomous geo-spatial positioning. It allows satellite navigation devices to determine their location (longitude, latitude, and altitude/elevation) to high p ...

Service site. WSRT observed galaxies in the Spitzer Infrared Nearby Galaxies Survey at wavelengths of 18cm and 22cm. The WSRT site is also hosting one of the two experimental EMBRACE (Electronic MultiBeam Radio Astronomy ConcEpt)

phased array In antenna theory, a phased array usually means an electronically scanned array, a computer-controlled array of antennas which creates a beam of radio waves that can be electronically steered to point in different directions without moving t ...

telescopes, part of the Phase 2 of the

Square Kilometre Array The Square Kilometre Array (SKA) is an intergovernmental international radio telescope project being built in Australia (low-frequency) and South Africa (mid-frequency). The combining infrastructure, the Square Kilometre Array Observatory (SK ...

(SKA) project.

References

External links

* {{Radio-astronomy Astronomical observatories in the Netherlands Buildings and structures in Drenthe Interferometric telescopes Midden-Drenthe Radio telescopes