Parkes’ dish is 60 years old, but it’s still making major scientific breakthroughs

CSIRO’s 64-meter Parkes radio telescope was commissioned on October 31, 1961. At the time, it was the most advanced radio telescope in the world, incorporating many innovative features that have since become standard in all antennas. parabolic.

Thanks to its first discoveries, it quickly became the flagship instrument of the genre. Today, 60 years later, it is still arguably the best satellite dish radio telescope in the world. He still performs world-class science and makes discoveries that shape our understanding of the Universe.

The origins of the telescope can be traced back to wartime radar research by the Radiophysics Laboratory, part of the Council for Scientific and Industrial Research (CSIR), the precursor of CSIRO. Atop the Sydney Cliffs in Dover Heights, the lab developed a radar for use in the Pacific Theater. At the end of World War II, the technology was redirected towards peaceful applications, including the study of radio waves from the Sun and beyond.

The first antennas were much simpler, not to say smaller. CSIRO, Author provided

In 1946, British physicist Edward “Taffy” Bowen was appointed head of the Radiation Physics Laboratory. He had been one of the brilliant engineers, nicknamed “boffins”, who developed the radar as part of the secret British pre-war military research. The Radiation Physics Laboratory had a dedicated radio astronomy group headed by the brilliant Joseph (Joe) Pawsey. Many of the group went on to become leaders in the nascent field of radio astronomy, including Bernie Mills, Chris Christiansen, Paul Wild, Ruby Payne-Scott (the first female radio astronomer) and John Bolton.

As the group’s initial research focused on the Sun’s radio waves, Bolton’s attention quickly shifted to identifying other sources further afield. By the early 1950s, Dover Heights radar dishes had discovered more than 100 sources of radio transmissions from the Milky Way and beyond, including signals from supernova explosions. These observations have made the Radiophysics Laboratory one of the world’s leading centers for radio astronomy.

By 1954, Dover Heights technology was outdated and obsolete, prompting Bowen to launch the next step in Australian radio astronomy: a new state-of-the-art radio telescope.

He decided that the most versatile option was to build a large, fully steerable satellite dish. The final price was A $ 1.4 million (A $ 25.6 million in current terms) – well over CSIRO’s budget at the time.

The Menzies government agreed to fund the project, on condition that at least 50% of the money came from the private sector. Through his wartime contacts, Bowen secured AU $ 250,000 each from the Carnegie Corporation and the Rockefeller Foundation, as well as a range of Australian private donations.

British firm Freeman Fox and Partners produced the detailed design, incorporating suggestions from legendary engineer Barnes Wallis, famous for “Dambusters”. Based on the available budget and the desired functionality, a diameter of 64 meters has been agreed for the dish.

1955 design by Barnes Wallis
1955 design notes by Barnes Wallis. CSIRO, Author provided

The site chosen was near the town of Parkes, about 350 km west of Sydney. This location had favorable weather conditions and was free from local radio interference. The local council has also enthusiastically offered to cover the cost of some of the earthworks.

In 2020, the local Wiradjuri people named the Murriyang Telescope, a traditional name meaning “Skyworld”.

Construction of the telescope began in September 1959 and was completed two years later. On October 31, 1961, Governor General William Sidney, Viscount de l’Isle, officially inaugurated the telescope in a ceremony attended by 500 guests.

The opening ceremony of the Parkes dish
The Governor General (center) greets guests at the opening ceremony of the telescope in 1961. CSIRO, Author provided

Decades of Discovery

John Bolton has been appointed founding director of the telescope. Under his dynamic decade-long tenure, astronomers made a series of important discoveries that made the parabola Australia’s first scientific instrument.

Astronomers have revealed the immense magnetic field of our Milky Way galaxy. A few months later, the telescope detected quasars, the most distant known objects in the Universe – a discovery that increased the size of the known Universe tenfold. To cap off a memorable first year, Parkes followed the very first interplanetary space mission, Mariner 2, when it flew over Venus in December 1962.

In the 1970s, researchers discovered and mapped the huge molecular clouds scattered throughout our galaxy. The study of pulsars – rotating stars that emit beams of radio waves, much like a lighthouse – has become a major area of ​​research. Parkes discovered more pulsars than all other radio observatories combined, including the only known dual pulsar system, spotted in 2003.

In the 1990s, the distribution of galaxies was mapped at a distance of 300 million light years, revealing the complex structure of the Universe. More recently, Parkes discovered the first Fast Radio Burst – a short, intense explosion of radio waves created by a still unknown process. The telescope has also been involved in extraterrestrial intelligence research (SETI), including the ten-year Breakthrough Listen project, which began in 2016.

To the public, the telescope is perhaps best known for its space tracking, especially its role in the Apollo lunar missions. But it also supported other important missions such as NASA’s Voyager 2, which flew over Uranus and Neptune in the 1980s and crossed interstellar space in 2018. By 1986, Parkes was the main tracking station of the European Giotto mission to Halley’s comet. And next year, Parkes will follow some of the first commercial lunar landers.

Parkes follows the Apollo Moon mission in 1969. CSIRO, author provided
Parkes follows the Apollo Moon mission in 1969. CSIRO, author provided

Originally intended to operate for 20 years, the longevity of the telescope is the result of constant improvements. Recent improvements include a new ultra-wideband receiver that can scan a wide range of radio frequencies, and “phased array feeds” (PAFs) developed by CSIRO that allow the telescope to observe up to 36 points in the field. sky at once. Work is currently underway on a cryogenically cooled PAF which, when installed in 2022, will double that number. With these upgrades in place, a single receiver can be used to deliver over 90% of Parkes’ current operations.

Construction workers building the dish
Construction only lasted two years. CSIRO, Author provided

It’s hard to say how long the Parkes dish will continue to run. It depends on future upgrades and whether the telescope structure remains in good working order. But astronomers will still need a large satellite dish.

Parkes has maintained its position as a world leader in radio astronomy by constantly adapting to new requirements. Today he is an icon of Australian science and achievement. Sixty years after looking up to the sky for the first time, the future still looks bright in Parkes.The conversation

Article by John Sarkissian, Operations Scientist, CSIRO

This article is republished from The Conversation under a Creative Commons license. Read the original article.

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