Down Under, 'the dish' looks to the heavens (photos)
CNET visits the Parkes Radio Telescope in rural Australia. Besides making important astronomical discoveries, the facility played a big role in broadcasting the Apollo 11 moon landing.
Welcome to Parkes
Just outside the town of Parkes in central New South Wales, Australia, sits one of the most prominent radio astronomy telescopes in the world.
Completed in 1961 and designed by the U.K. firm Freeman Fox & Partners (which also engineered the Sydney Harbour bridge), "the dish" has been a pioneering facility in the exploration of space. It has, among other things, discovered more than 700 pulsars (about half of all known pulsars in the universe), mapped the Milky Way Galaxy and detected its magnetic field, and surveyed neighboring galaxies out to a distance of 300 million light-years by searching for neutral hydrogen.
What's more, Parkes has played a vital role in tracking the Mariner II, Voyager II, and Galileo space probes, and almost every Apollo flight, including the Apollo 11 moon landing. The 2000 film "The Dish," starring Sam Neil, tells the Apollo 11 story, while fictionalizing some details.
If you've seen the movie, you'll recognize this view of the radio telescope down the tree-shaded drive. Sheep no longer roam the grounds as they did on the big screen, but the telescope dominates the flat and pastoral landscape around it.
Visitors enter the Observatory grounds through a small museum. Australia's Commonwealth Scientific and Industrial Research Organization (CSIRO) has additional radio telescopes in Narrabri and Coonabarabran, both in New South Wales, and it is building an array of 36 antennas in remote Western Australia.
The agency also operates the Canberra Deep Space Complex in conjunction with NASA. Located just outside the national capital of Canberra, the complex works with stations near Madrid and in Fort Irwin, Calif., to communicate with both manned spacecraft and deep-space probes.
The dish measures 64 meters (210 feet) across and has a surface area of 3,216 square meters (34,616 square feet). If filled with water, it could hold 15,837 cubic meters (4.2 million gallons). So, yeah, it's pretty big.
The smaller, 18-meter (59-foot) Kennedy dish was transferred to Parkes in 1963 from a now-closed facility outside of Sydney. Although it's no longer in use, it's mounted on rails and can be moved by a tractor engine to vary the distance between it and the main dish. During the Apollo program, it also functioned as an uplink antenna. A third 12-meter dish (39.4 feet) that's used to test technologies for the facility in Western Australia sits out of sight.
The curved surface of the dish, which is made of solid-steel plates, perforated aluminum panels, and galvanized-steel mesh, collects radio waves from space and focuses them up to the cabin at the end of the three legs. The cabin sits 26 meters (85.3 feet) above the center of the parabolic surface for a total height of 58 meters (157.5 feet).
Inside the focus cabin are microwave and radio receivers that can collect waves from 13 points in the sky simultaneously. The receiver then turns the radio waves into electrical signals, which travel down the legs to computers that amplify the signals and remove interference.
The dish has a focal length of 27.5 meters (89.9 feet) and is now 10,000 more times sensitive than when it was built. In other words, it could detect a cell phone transmission from Pluto.
The dish weighs 300 tons and is balanced by a 350-ton counterweight. There's another 700 tons in the base above the three-story control tower, which houses a radio equipment room and the computers used necessary to point the dish.
When pointing straight up, the dish is in its "stowed" position. Technicians put it there when the dish is not in use or when winds are faster than 35 kilometers per hour (21.7 miles per hour). During the Apollo 11 landing, however, the dish kept operating, even as winds reached 110 kilometers per hour (68 miles per hour).
As mentioned, the Parkes Radio Telescope played an important role in bringing images of the Apollo 11 moon landing to the world on July 20, 1969 (July 21 in Australia). As the sign says, the station in Canberra transmitted the first 8 minutes of footage, but the Parkes telescope ended up receiving most of the 2.5-hour broadcast. A small plaque outside commemorates the event.