The Parkes radio telescope in NSW.

About 'the Dish'

CSIRO's Parkes radio telescope is a 64-m diameter parabolic dish used for radio astronomy.

• 19 April 2011 | Updated 1 May 2012

• The Telescope
• Using the Telescope
• Radio Astronomy

The Telescope

CSIRO's Parkes radio telescope is a 64-m diameter parabolic dish used for radio astronomy. It is located about 20 km north of the town of Parkes, New South Wales (NSW), and about 380 km west of Sydney.

It is operated by CSIRO Astronomy and Space Science (CASS), a business unit of CSIRO. CASS also operates the Australia Telescope Compact Array near Narrabri, NSW, and the Mopra radio telescope near Coonabarabran, NSW, and is developing the Australian SKA Pathfinder (ASKAP) telescope in Western Australia.

The telescope was built in 1961, but only its basic structure has remained unchanged. The surface, control system, focus cabin, receivers, computers and cabling have all been upgraded - some parts many times - to keep the telescope current.

The telescope is now ten thousand times more sensitive than when commissioned in 1961.

Using the Telescope

The telescope operates twenty four hours per day, through rain and cloud. About 85 per cent of all time each year is scheduled for observing. Less than five per cent of that is lost because of high winds or equipment problems. Most of the rest of the time each year is used for maintenance and testing. Around 300 researchers use the telescope each year, and more than 40 per cent of these users are from overseas.

The moving part of the dish is not fixed to the top of the tower but just sits on it. Because the large surface catches the wind like a sail, the telescope must be 'stowed' (pointed directly up) when the wind exceeds 35 km an hour.

Radio Astronomy

The radio waves from objects in space are extremely weak by the time they reach Earth. The power received from a strong cosmic radio source by the Parkes telescope is about a hundredth of a millionth of a millionth of a watt (10^-14 W). If you wanted to heat water with this power it would take about 70 000 years to heat one drop by one degree Celsius.

Galaxies contain stars, gas and dust. The gas - mostly hydrogen - is the raw material from which stars form. It emits radio waves, at a frequency of 1420 MHz. Radio astronomers spend a lot of time studying this gas, learning where it is and how it is moving.

Astronomers don't look through the telescope. Instead, signal processing systems and computers take the radio waves the telescope collects and turns them into pictures (like photographs) of objects in space.