Telescope Receivers to Turn into High-Speed Cameras

Receivers on the Westerbork Synthesis Radio Telescope will become high-speed cameras, expanding the instrument’s field of view by more than a factor of 30 and increasing its frame rate to 10,000 per second. The upgrade will enable astronomers to survey the sky with greater sensitivity to quick changes.

The Apertif receivers allow astronomers to sensitively scan the sky for radio galaxies that are mostly unchanging. However, throughout the galaxy, many short, bright radio bursts lasting less than one-thousandth of a second occur. Some of these are emitted by radio pulsars — spinning galactic lighthouses — but others originate from far outside our galaxy. The nature of these far-off bursts is unclear, but given their distance, they must represent enormous explosions comparable to the supernovas that are observed when massive stars explode.

Under a €540,000 (about $700,700) grant from the Netherlands Organization for Scientific Research, a team of Dutch astronomers and engineers led by Joeri van Leeuwen of ASTRON (Netherlands Institute for Radio Astronomy) will sharpen the receivers’ ability to see; the group also will extend the algorithms on the current imaging chips to form 10,000 frames per second. An extra supercomputer will increase the image processing capacity so the data received from the telescope will be processed immediately.

The new field of view (the large hexagon) of the Apertif receivers on the Westerbork telescope is 30 times bigger than the old one (central circle) and the full moon. With the new high-speed cameras, astronomers will be able to detect weak and rare cosmic flashes. Recently, with the test system, two fast blinking pulsars were observed simultaneously. These flashes are visible at the bottom right. Courtesy of ASTRON.

The Apertif’s phased array feeds and burst-detection processing are pathfinder technologies for the Square Kilometer Array (SKA). Slated to be the world’s largest and most sensitive radio telescope, the array will link radio wave receptors in Australia and South Africa to create a telescope with a collecting area equivalent to a dish with an area of about one square kilometer. Construction is scheduled to start in 2016.

The Westerbork telescope, operated by ASTRON, is an aperture synthesis interferometer near camp Westerbork. It consists of a linear array of 14 antennas, which can be individually directed to any point on the sky, with a diameter of 25 m arranged on a 2.7-km east-west line. Ten of the dishes have a fixed location, while two at the eastern end of the array can be moved on rail tracks. The telescope was completed in 1970 and underwent an upgrade between 1995 and 2000.

For more information, visit: www.astron.nl