High-tech part of new-gen radio telescope passes first test

Washington, August 13 : The Expanded Very Large Array (EVLA), part of the National Radio Astronomy Observatory (NRAO), has passed its first test of advanced digital hardware, designed to combine signals from its upgraded radio-telescope antennas to produce high resolution images of celestial objects.

By upgrading the 1970s-era electronics of its original Very Large Array (VLA), NRAO is creating a major new radio telescope that is ten times more sensitive than before.

Using the EVLA, astronomers will observe fainter and more-distant objects than previously possible and use vastly improved analysis tools to decipher their physics.

The heart of the new electronics that makes this transformation possible is a high-performance, special-purpose supercomputer, called the WIDAR Correlator.

It has been designed and is being built by the National Research Council of Canada at the Dominion Radio Astrophysical Observatory (DRAO) of the Herzberg Institute for Astrophysics.

The design of the correlator incorporates an NRC-patented new digital electronic architecture.

The successful test, at the VLA site 50 miles west of Socorro, New Mexico, used prototype correlator electronics to combine the signals from two upgraded VLA antennas to turn them into a single, high-resolution telescope system, called an interferometer.

Each upgraded EVLA antenna produces 100 times more data than an original VLA antenna. When all 27 antennas are upgraded, they will pump data into the WIDAR correlator at a rate equal to 48 million digital telephone calls.

To process this torrent of data, the correlator will make 10 million billion calculations per second.

Powerful, multi-antenna imaging radio-telescope systems use pairs of antennas as their basic building blocks.

Each of the VLA's 27 giant dish antennas is combined electronically with every other antenna to form a multitude of pairs. Each pair contributes unique information that is used to build a highly- detailed image of some astronomical object.

The successful two-antenna test thus verifies the design of the new correlator.

According to Fred Lo, Director of the National Radio Astronomy Observatory, "This achievement marks the first time that the complete chain of electronics for the EVLA has worked together, and represents a huge milestone in the project."

ANI