The WIDAR system is up and running

Ken Tapping's weekly astrophysics column from the Herzberg Institute

A great thing about working at the Dominion Radio Astrophysical Observatory is rubbing shoulders with some extremely smart people. It makes every day a learning experience. A measure of exactly how smart they are is their recent, successful development of the biggest radio astronomical signal processing system in existence.

One of the memorable scenes in the movie “Contact” shows the heroine, played by Jodie Foster, sitting amidst the antennas of the Very Large Array radio telescope, at Socorro, New Mexico. When it was opened in 1978, this instrument, consisting of twenty-seven 25-metre dishes, was the biggest and most sensitive in the world. Its performance was never bettered. However, changing scientific needs and technological advances made a dramatic upgrade feasible, to provide an instrument about 100 times more sensitive and 8,000 times more capable.

Unfortunately, this huge increase in capability brought with it a serious problem. If the stream of data coming from the previous version of the VLA were likened to a flood, the output of the Expanded VLA would be a tsunami. New technologies that did not exist would be needed to process it. Moreover, since the new instrument would be operating continuously, the data would have to be dealt with as fast as it is produced. That is where the National Research Council and the engineers at our observatory came in.

Canada,through the National Research Council, is involved in a number of international collaborations to develop and operate new astronomical facilities. As part of one of those collaborations, a team of engineers at our observatory came up with a possible solution for the EVLA data-handling problem. This new concept in signal processing was called WIDAR.  In return Canadian astronomers would have access to this world-leading radio telescope, and other instruments.

The deal was accepted, and the design and construction started. It required the development of new signal processing chips, special circuit boards and control systems. The completed device contains 300 circuit boards, each of which is made up of 28 layers of circuitry.

At our observatory equipment racks started to fill with modules loaded with the circuit boards. At DRAO WIDAR could only be tested in parts, because the power demands of the whole system exceeded the observatoryís electricity supply. As the racks were completed they were shipped to Socorro. At the end of March the DRAO team followed for the formal “switch-on” and a celebration of the success of this international effort and a unique example of Canadian innovation.

The first radio images are rolling off the production line, and astronomical research will soon be getting a big boost, driven by observations that were simply not possible a few years ago.

Jupiter is low in the west after sunset; Venus is higher up and brilliant. Mars is high in the Southeast; Saturn rises about 8 pm. The Moon will be new on the 20th.

Ken Tapping is an astronomer with the National Research Council’s Herzberg Institute of Astrophysics, and is based at the Dominion Radio Astrophysical Observatory, Penticton.