Parkes Observatory


Parkes Observatory is a radio astronomy observatory, located 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, as part of the Australia Telescope National Facility network of radio telescopes. It is frequently operated together with other CSIRO radio telescopes, principally the array of six dishes at the Australia Telescope Compact Array near Narrabri, and a single dish at Mopra, 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 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 movable dish telescope, second largest in the Southern Hemisphere, and one of the first large movable dishes in the world.
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 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 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:
  • receiver '
  • The Multibeam Receiver – a 13-horned receiver cooled at for the Hydrogen line.
  • H-OH receiver '
  • GALILEO receiver
  • 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, covering 8.1-8.5 GHz
  • KU-BAND, covering 12–15 GHz
  • 13MM, covering 16–26 GHz
  • Ultra Wideband Low receiver – installed in 2018 it can simultaneously receive signals from 700 MHz to 4 GHz. It is cooled to to minimise noise and will enable astronomers to work on more than one project at once.

    18m "Kennedy Dish" antenna

The "Kennedy Dish" antenna was transferred from the Fleurs Observatory 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 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 array.

Astronomy research

Timeline

1960s
  • Built in 1961 and was fully operational by 1963.
  • A 1962 series of lunar occultations of the radio source 3C 273 observed by the Parkes Telescope were used to locate its exact position, allowing astronomers to find and study its visual component. Soon to be called "quasi-stellar radio sources", Parkes observation was the first time this type of object to be associated with an optical counterpart.
  • 1964 to 1966, all-sky survey at 408 MHz of the southern sky is conducted and published finding over 2000 radio sources including many new quasars.
  • Second all-sky survey at 2,700 MHz begins in 1968.
1990s
2000s
s were discovered in 2007 when Duncan Lorimer of West Virginia University assigned his student David Narkevic to look through archival data recorded in 2001 by the Parkes radio dish.
Analysis of the survey data found a 30-jansky dispersed burst which occurred on 24 July 2001, less than 5 milliseconds in duration, located 3° from the Small Magellanic Cloud. At the time it was theorised FRBs might be signals from another galaxy, emissions from neutron stars or black holes. More recent results confirm that magnetars, a kind of highly magnetised neutron star, may be one source of fast radio bursts.

Peryton discovery

In 1998 Parkes telescope began detecting fast radio bursts and similar looking signals named perytons. Perytons were thought to be of terrestrial origin, such as interference from lightning strikes. In 2015 it was determined that perytons were caused by staff members opening the door of the facility's microwave oven during its cycle. When the microwave oven door was opened, 1.4 GHz microwaves from the magnetron shutdown phase were able to escape. Subsequent tests revealed that a peryton can be generated at 1.4 GHz when a microwave oven door is opened prematurely and the telescope is at an appropriate relative angle.

Breakthrough Listen

The telescope has been contracted to be used in a search for radio signals from extraterrestrial technologies for the heavily funded project Breakthrough Listen. The principal role of the Parkes Telescope in the program will be to conduct a survey of the Milky Way galactic plane over 1.2 to 1.5 GHz and a targeted search of approximately 1000 nearby stars over the frequency range 0.7 to 4 GHz.

Historical non-astronomy research

During the Apollo missions to the Moon, the Parkes Observatory was used to relay communication and telemetry signals to NASA, providing coverage for when the Moon was on the Australian side of the Earth.
The telescope also played a role in relaying data from the NASA Galileo mission to Jupiter that required radio-telescope support due to the use of its backup telemetry subsystem as the principal means to relay science data.
The observatory has remained involved in tracking numerous space missions up to the present day, including:
To assist in a busy spaceflight period at the end of 2003 to early 2004, the Canberra Deep Space Communication Complex incorporated the Parkes dish. NASA upgraded the antenna through the CDSCC with new receivers and equipment capable of handling transmissions from robotic spacecraft. When its research time allows, Parkes can act as a spare 'ear' for CDSCC during times of high activity. While being used thus it is designated as DSS -49.
The CSIRO has made several documentaries on this observatory, with some of these documentaries being posted to YouTube.