Parkes Observatory is a radio astronomy observatory, located 20 kilometres (12 mi) north of the town of Parkes, New South Wales, Australia. It hosts Murriyang, the 64 m CSIRO Parkes Radio Telescope also known as "The Dish", along with two smaller radio telescopes. The 64 m dish was one of several radio antennae used to receive live television images of the Apollo 11 Moon landing. Its scientific contributions over the decades led the ABC to describe it as "the most successful scientific instrument ever built in Australia" after 40 years of operation. The Parkes Observatory is run by the Commonwealth Scientific and Industrial Research Organisation (CSIRO), as part of the Australia Telescope National Facility (ATNF) network of radio telescopes. It is frequently operated together with other CSIRO radio telescopes, principally the array of six 22-metre (72 ft) dishes at the Australia Telescope Compact Array near Narrabri, and a single 22-metre (72 ft) dish at Mopra (near Coonabarabran), together with other radio telescopes in Australia, and other countries, to form a very long baseline interferometry array. The observatory was included on the Australian National Heritage List on 10 August 2020.
Design and construction The Parkes Radio Telescope, completed in 1961, was the brainchild of E. G. "Taffy" Bowen, chief of the CSIRO's Radiophysics Laboratory. During the Second World War, he had worked on radar development in the United States and had made connections in its scientific community. Calling on this old boy network, he persuaded two philanthropic organisations, the Carnegie Corporation and the Rockefeller Foundation, to fund half the cost of the telescope. It was this recognition and key financial support from the United States that persuaded Australian prime minister, Robert Menzies, to agree to fund the rest of the project. The Parkes site was chosen in 1956, as it was accessible, but far enough from Sydney to have clear skies. Additionally the mayor Ces Moon and landowner Australia James Helm were both enthusiastic about the project. The success of the Parkes telescope led NASA to copy features of the design into their Deep Space Network, which included three 64-metre (210 ft) dishes built at Goldstone, California, Madrid, Spain, and Tidbinbilla, near Canberra in Australia. The telescope continues to be upgraded, and as of 2018 is 10,000 times more sensitive than its initial configuration.
Radio telescope
Hardware
The primary observing instrument is the 64-metre (210 ft) movable dish telescope, second largest in the Southern Hemisphere, and one of the first large movable dishes in the world (DSS-43 at Tidbinbilla was extended from 64-metre (210 ft) to 70-metre (230 ft) in 1987, surpassing Parkes). The inner part of the dish is solid aluminium and the outer area a fine aluminium mesh, creating its distinctive two-tone appearance. In the early 1970s the outer mesh panels were replaced by perforated aluminium panels. The inner smooth plated surface was upgraded in 1975 which provided focusing capability for centimetre- and millimetre-length microwaves. The inner aluminium plating was expanded out to a 55 metres (180 ft) diameter in 2003, improving signals by 1dB. The telescope has an altazimuth mount. It is guided by a small mock-telescope placed within the structure at the same rotational axes as the dish, but with an equatorial mount. The two are dynamically locked when tracking an astronomical object by a laser guiding system. This primary-secondary approach was designed by Barnes Wallis.
Receivers
The focus cabin is located at the focus of the parabolic dish, supported by three struts 27 metres (89 ft) above the dish. The cabin contains multiple radio and microwave detectors, which can be switched into the focus beam for different science observations. These include:
1,050-centimetre (34.4 ft) receiver (Replaced now by UWL) The Multibeam Receiver – a 13-horned receiver cooled at −200 °C (−328.0 °F; 73.1 K) for the 21-centimetre (8.3 in) Hydrogen line. H-OH receiver (Replaced now by UWL) GALILEO receiver (Replaced now by UWL) AT multiband receivers, covering 2.2-2.5,4.5-5.1 and 8.1-8.7 GHz METH6, covering 5.9-6.8 GHz MARS (X band receiver), covering 8.1-8.5 GHz KU-BAND, covering 12–15 GHz 13MM (K band receiver), covering 16–26 GHz Ultra Wideband Low (UWL) receiver – installed in 2018 it can simultaneously receive signals from 700 MHz to 4 GHz. It is cooled to −255 °C (−427.0 °F; 18.1 K) to minimise noise and will enable astronomers to work on more than one project at once.
18m "Kennedy Dish" antenna The 18-metre (59 ft) "Kennedy Dish" antenna was transferred from the Fleurs Observatory (where it was part of the Mills Cross Telescope) in 1963. Mounted on rails and powered by a tractor engine to allow the distance between the antenna and the main dish to be easily varied, it was used as an interferometer with the main dish. Phase instability due to an exposed cable meant that its pointing ability was diminished, but it was able to be used for identifying size and brightness distributions. In 1968 it successfully proved that Radio galaxy lobes were not expanding, and in the same era contributed to Hydrogen line and OH investigations. As a stand-alone antenna it was used in studying the Magellanic Stream. It was used as an uplink antenna in the Apollo program, as the larger Parkes telescope is receive-only. It is preserved by the Australia Telescope National Facility.
Australia Telescope National Facility The observatory is a part of the Australia Telescope National Facility network of radio telescopes. The 64-metre (210 ft) dish is frequently operated together with the Australia Telescope Compact Array at Narrabri, the ASKAP array in Western Australia, and a single dish at Mopra, telescopes operated by the University of Tasmania as well as telescopes from New Zealand, South Africa and Asia to form a Very Long Baseline Interferometry (VLBI) array.
Astronomy research
Timeline 1960s
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