Made up of six identical antennas, the Australia Telescope Compact Array is used by astronomers to study the structure and evolution of our Universe.
Located outside Narrabri in north-west New South Wales, about 500 kilometres from Sydney, our Compact Array telescope is one of three instruments that make up the Australia Telescope National Facility. Radio signals detected by the telescope's six 22-metre antennas are combined to provide more detailed images than a single large dish could achieve.
Research with the Compact Array
The Compact Array began operating in 1988 and has since been upgraded to ensure that it remains at the leading edge of radio astronomy research.
It is used by more than 100 observing teams each year to study subjects including:
- early stages of star formation, and the late stages of the lives of stars
- molecules in space
- supernovae – exploding stars – and the radio-emitting debris left by the explosions
- magnetic fields in galaxies
- radio-emitting jets of material from black holes
- how hydrogen gas – the raw material for stars – is distributed in the local Universe.
Among its most high-profile achievements are capturing the first 3D picture of the radiation belts around Jupiter, the first good evidence linking exploding stars with flashes of gamma rays, and the first image showing how gas churns in interstellar space.
Fast facts about the Compact Array
- The telescope was funded as a project for Australia's Bicentennial in 1988.
- It was officially opened on 2 September 1988 by the Hon. Bob Hawke AC MP, Prime Minister of Australia at the time.
- Five of the Compact Array's six dishes sit on a three kilometre stretch of wide-gauge rail track running east–west, the sixth antenna is located three kilometres further west; there is also a 214 metre track running north–south.
- The antennas are not moved along the track while observations are taking place, but in between observations – every few weeks or so; they move along the track at four kilometres per hour, a fast walking pace.
- Signals received by the six antennas are combined to give a high-resolution radio 'picture'; this technique is known as 'interferometry'.
- The telescope can receive radio signals from three millimetres to 20 centimetres long.
- It can be pointed with an accuracy of better than two arcseconds – the width of a finger seen from one kilometre away.
- It operates 24 hours a day, seven days a week, throughout the year.
- About 80 per cent of all time each year is scheduled for observing, and less than five per cent of that is lost because of high winds, bad weather or equipment problems; the rest of the time each year is used for maintenance and testing.
- The Compact Array is one of the most advanced telescopes of its type (of which there are about a dozen in the world); it is among the top three telescopes of its kind by both publication numbers and citations.