Narrabri's Australia Telescope Compact Array
Radio Telescopes
The Australia Telescope Compact Array [ATCA] at Narrabri is one of the world’s advanced radio telescopes and the only one of its kind in the Southern Hemisphere. A set of six 22-metre dishes (antennas) are moved regularly over 6km (3.73 miles) on a wide gauge rail track to receive the best possible images and radio waves from space.
The Compact Array provides high resolving power (more detail) than signals from a large single dish.
The Australia Telescope was originally suggested in 1974-75 as an interferometer based at Parkes to extend the existing Parkes Radio Telescope’s power. The project was originally known as the Australian Synthesis Telescope [AST].
Committee members from CSIRO, University of Sydney and Australian National University’s Mount Stromlo Observatory debated whether this new instrument should be another large single dish whilst others favoured many small dishes.
The Committee finally agreed on many small dishes in 1978. The project was already underfunded at only $9 million during the 1980s, so it faced a dwindling chance of success. The Government rejected the AST proposal.
In 1981, Dr Robert (Bob) Frater, the Chief of CSIRO’s Division of Radiophysics at Parkes expressed concern regarding the project and the proposed site in 1981. He believed it was “too narrow in scope: not innovative enough,” insufficiently funded and likely to have a “short scientific life”.
The site location was changed to Narrabri where an observatory housing Radiophysic’s radioheliograph (an instrument for studying the Sun’s radio waves) was closing down.
This new design accommodated the astronomical community’s many groups, including high-frequency spectral-line mapping for covering wide ranges of wavelengths, and for Long and Very Long Baseline Interferometry [VLBI]. They gave it the thumbs up.
Funding from the Federal Government was finally approved in August 1982 after months of lobbying. Celebrations soon proved premature as a change of government in 1983 put the project on hold once more.
Cabinet finally approved the project in November 1983, after several anxious months, and a Parliamentary Public Works Committee’s hearing.
CSIRO submitted their design to consulting engineers, Macdonald Wagner and Priddle, for six antennas.
Construction of the Compact Array took five years, costing $50 million. It was also designated as an official Bicentennial Project so they were on a tight deadline.
Radio Telescope received the first correlated signal in August 1988.
Prime Minister Robert (Bob) Hawke led the official opening on 2 September 1988 on a very windy day, with the Minister for Science Barry Jones and Bob Frater present.
A torrential downpour occurred during the after-party. Guests danced on the tables once the outdoor marquee’s floor was soaked.
The Compact Array became the first millimetre-wave interferometer after new space-age technology was installed and tested on 30 November.
The Australia Telescope National Facility (ATNF), a division of CSIRO, operates the Compact Array.
The ATNF also operate the Parkes Radio Telescope (featured in The Dish).
Sources:
Australia Telescope Compact Array
Narrabri Visitors Centre and How To Get There
Radio Telescopes at Narrabri.
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Five 22-metre antennas at Narrabri.
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Large Magellanic Cloud: combined Parkes/ ATCA data
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Supernova 1998bw in the spiral galaxy ESO184-G82.
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SNR1987A imaged by the ATCA in August 2003.
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