On this Day: ‘The Dish’ radio telescope opens
IT WAS A WARM and blustery day on 31 October 1961, when Australia’s Parkes Observatory was officially inaugurated.
Twenty kilometres north of the town of Parkes in central-western NSW, gusts whipped through the shallow valley where the newly completed structure towered. The winds were so strong that ladies had to secure their hats, the speeches from dignitaries were barely audible and the plan for a demonstration rotation of the dish had to be scrapped.
Nonetheless, this radio telescope – which took 10 years of planning and design – was part of a new generation of radio telescopes, and it secured a spot for Australia at the forefront of space discovery.
“The Dish is an icon of Australian science,” says Dr Phil Diamond, Chief of CSIRO Astronomy and Space. “[And] is still one of the best-performing radio telescopes in the world today.” Only the Very Large Array telescope in the US, and CSIRO’s Compact Array in Narribri, NSW, beat it for picking up finer details in space, he says.
The Parkes radio telescope in central-western NSW. (Credit: CSIRO)
The Moon landings
Parkes is best known for transmitting video footage of the first Moon landing to 600 million people across the world – as depicted in the 2000 film The Dish – but it has many other radio astronomy firsts under its belt too.
On 21 July 1969, Parkes was one of two Australian stations (the first being Canberra’s Honeysuckle Creek) to receive the signal from the Apollo 11 spacecraft when the Moon was hidden from Earth’s Northern Hemisphere. The wind was also whipping around the dish at around 100km/h that night, but for more than two hours it relayed the video footage of the moonwalk, which Australians saw around 300 milliseconds before the rest of the world.
One year later, Parkes also played a crucial role in helping the crippled Apollo 13 spacecraft return to Earth after a failed Moon landing. The craft’s oxygen tank exploded two days into the mission. As the power on board plummeted, the only option the crew had was to orbit to around the far-side of the Moon and head straight back to Earth. Parkes was called on to track the ship and relay information to NASA. At one point the tracking data showed it veering off course; without Parkes’ monitoring of its journey, Apollo 13 wouldn’t have been able to correct its path and safely re-enter Earth’s atmosphere.
The 2000 film “The Dish” portrayed a dramatised account of the Parkes Observatory’s role in the 1969 Moon landing.
Quasars and pulsars
Constant adjustments over the past 50 years are part of the reason that the telescope has remained relevant to astronomers. The 64m dish is much more powerful now, and about 10,000 times more sensitive, than it was in 1961. While its general structure appears unchanged, its surface panels, focus cabin, receiving equipment, control panel and data processors have all been replaced.
“Parkes has had several surface upgrades, each of which have extended the frequency range of the telescope,” Phil says. The standout new technology, is the multi-beam receiver, which allows the telescope to see much more of the sky at once. “This has been the mainstay of much of what Parkes has achieved in recent years,” he says.
Thanks to its large collecting area, the dish is ideally suited to finding pulsars – spinning neutron stars that blast out powerful beams of radiation. And in fact it has discovered more than two thirds of the 2000 known pulsars, Phil says. In 1963 Parks is also credited with helping astronomers discover the first quasar – compact and incredibly bright regions that surround the supermassive black holes in the centre of distant galaxies. These can sometimes equal the luminosity of one trillion suns.
More recently the telescope has been used to map and analyse our galaxy. The HI Parkes All-Sky Survey, which began in 1997, has found more than 2500 new galaxies in our region.
The fact that the Parkes model has been copied by observatories the world over is a testament to its success. Matching 64m dishes installed in Madrid, California and Canberra make up NASA’s Deep Space Network: a massive telecommunications system capable of keeping in constant contact with spacecraft as the Earth rotates.
In August 2020, the Parkes radio telescope was officially added to the National Heritage List.
“The Dish is part of Australia’s proud cultural and scientific history and to this day continues to serve as an important tool in our understanding of the Universe,” said Minister for Industry, Science and Technology Karen Andrews
“While the Parkes telescope may be old enough to qualify for the National Heritage List, it continues to operate as one of the world’s leading astronomy instruments, observing the Universe day and night, seven days a week, with the most advanced radio receiver systems in the world,” CSIRO Chief Executive Dr Larry Marshall.
Find a timeline of the telescope’s achievements over the last 50 years on CSIRO Science site here.
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