Westerbork Synthesis Radio Telescope


The Westerbork Synthesis Radio Telescope is an aperture synthesis interferometer near World War II Nazi detention and transit camp Westerbork, north of the village of Westerbork, Midden-Drenthe, in the northeastern Netherlands.

Overview

It consists of a linear array of 14 antennas with a diameter of 25 metres arranged on a 2.7 km East-West line. It has a similar arrangement to other radio telescopes such as the One-Mile Telescope, Australia Telescope Compact Array and the Ryle Telescope. Its Equatorial mount is what sets it apart from most other radio telescopes, most of which have an Altazimuth mount. 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 four dishes are movable along two rail tracks. The telescope was completed in 1970 and underwent a major upgrade between 1995-2000.
The telescopes in the array can operate at several frequencies between 120 MHz and 8.3 GHz with an instantaneous bandwidth of 120 MHz and 8092 line spectral resolution. The WSRT is often combined with other telescopes around the world to perform very-long-baseline interferometry observations, being part of the European VLBI Network. The telescope is operated by ASTRON, the Dutch foundation for astronomy research.
As of writing, the WSRT is undergoing a major upgrade started in 2013 as part of the APERTIF project, where the current detectors are replaced with focal-plane arrays. This will allow a 25x larger field of view and will be used for large scale surveys of the northern sky, bringing back focus on the Hydrogen line for which it was originally designed, but also large pulsar searches and other science. The Telescope has been out of operation since 2015 and is planned to be back in full operation in winter 2019.
The WSRT is also an International GNSS Service site.
WSRT observed galaxies in the Spitzer Infrared Nearby Galaxies Survey at wavelengths of 18 and 22 cm.
The WSRT site is also hosting one of the two experimental EMBRACE phased array telescopes, part of the Phase 2 of the Square Kilometre Array project.