Moon landing 50th anniversary: a joint initiative with CSIRO

Drive 20km north of Parkes in New South Wales and you glimpse the dish from the highway.

Turn down the road to the observatory and it comes into view again and again, getting bigger each time.

A graceful steel bowl 64 metres across sits on a three-storey tower, held in place only by gravity.

Astronomers tilt and turn this dish ever mindful of the wind, which could pull the big sail off its perch.

Look up through the dish's perforated panels and you may see the Moon, it too tethered to Earth by gravity.

Radio signals from space reflect off the dish into an equipment cabin high above.

Here the signals are converted into tiny electrical currents then amplified a thousand million times.

The currents feed down into the telescope where they are processed into data that helps astronomers make sense of the universe.

The dish's origins go back to the Second World War when CSIRO assembled a crack team of engineers and scientists to work on radar.

At the war's end CSIRO kept this bunch of winners together and they explored new paths including the young science of radio astronomy - learning about the sun, stars and galaxies from the radio waves they emit.

Using small dishes and wires strung on poles, the CSIRO group quickly made discoveries and became a world leader.

In the 1950s the UK was planning a much bigger dish that could be turned to look at all parts of the sky, and CSIRO decided it wanted one too.

The site had to be easily reached from the astronomers' Sydney headquarters and sheltered from stray radio signals made by machinery and electrical equipment.

The Parkes site looked good and Parkes mayor Cec Moon was keen for the telescope to come there.

The telescope was designed by Freeman Fox (the company that had designed the Sydney Harbour Bridge) and the steelwork built by German firm M.A.N.

Governor-General Lord De L'Isle opened it on October 31, 1961 in front of 500 dignitaries.

NASA had not yet built its own large dishes and the Parkes telescope's design influenced NASA's antenna at Goldstone, opened in 1966 as a 64-metre dish like Parkes.

But the two dishes were not identical and there was one difference which would be crucial for Apollo 11; Goldstone and other NASA dishes could tilt further down towards the horizon.

Parkes quickly made its mark as a research instrument and in 1962, it helped identify the first quasar - a hugely energetic galaxy powered by a black hole.

It also went on to confirm the existence of magnetic fields in space, study cosmic molecules, and locate more of the small stars called pulsars than any other telescope.

Frequent upgrades have kept the telescope current: its control and receiving systems have been improved so much that it's now 10,000 times better at detecting weak signals than when it was built.

Parkes has now tracked more than a dozen spacecraft but most of its time is spent doing astronomy, often working with other telescopes.
