An eye on the radio sky
The Westerbork Synthesis Radio Telescope (WSRT) is a linear array of fourteen 25-meter radio telescopes. The dishes are arranged along a 2.7-kilometer east-west line. Ten of the telescopes are fixed in position, while four are movable along railway tracks, allowing astronomers to change the telescope's configuration for different observations. Completed in 1970, the WSRT uses a technique called aperture synthesis. By combining the signals from all individual dishes, the array functions as a single, much larger telescope, capable of producing high-resolution images of the radio sky.
The telescope's design is distinct. Unlike many modern radio telescopes that use an alt-azimuth mount, the WSRT dishes have an equatorial mount. This design keeps the detectors at a constant orientation to the sky during an observation, which is particularly effective for research on polarized radio waves. The observatory operates across a wide range of frequencies, from 120 MHz to 8.3 GHz. The WSRT is operated by ASTRON, the Netherlands Institute for Radio Astronomy, and it frequently participates in Very Long Baseline Interferometry (VLBI) observations, linking with telescopes worldwide to create a virtual Earth-sized instrument.