China launches world’s largest radio telescope, 500m in diameter

A 500-metre (1,640-ft.) aperture spherical telescope (FAST) is seen at the final stage of construction, among the mountains in Pingtang county, Guizhou province, China © Stringer
The biggest radio telescope located in China’s Guizhou Province is now operational. Featuring a reflector the size of 30 football pitches, it took five years and $180 million to construct.

Called the Five-hundred-meter Aperture Spherical Telescope's (FAST), the telescope is located in a karst valley in Pingtang County, a mountainous area in southwest China.

Some 8,000 local residents were relocated to ensure a 5km radio silence zone around the facility. About $269 million were allocated to pay compensations to the villagers.

The name FAST referrers to the main structure of the gigantic instrument, which has 4,450 triangular 11-meter panels and measures 500 meters in diameter. For comparison, the Arecibo Observatory in Puerto Rico, which held the title of world's largest radio telescope before FAST, has a 305-meter dish.

FAST was first brought online in July for trial observation and received a set of data from a pulsar about 1,351 light-years away, as Xinhua news agency was told by Qian Lei, an associate researcher with the National Astronomical Observation (NAO) under the Chinese Academy of Sciences, which built the project.

China plans to use one of its best supercomputers, the SkyEye-1, to process the massive amounts of data supplied by FAST. At its peak the data flow is expected to require computing power of over 200 teraflops per second.

The instrument would be used to study gravitational waves, stellar radio emissions and potentially signals from extraterrestrial civilizations, Qian Lei, an associate researcher with the National Astronomical Observatories of the Chinese Academy of Sciences, told state broadcaster CCTV.

“In theory, if there is civilization in outer space, the radio signal it sends will be similar to the signal we can receive when a pulsar [spinning neutron star] is approaching us,” Qian said.

FAST is the world's biggest radio telescope with a single dish. The old Soviet RATAN-600 in southern Russia is bigger still, but, unlike China's new telescope, its 576-meter reflector structure resembles a donut.

RATAN-600 radio telescope with a 600 diameter dish set at the Special Astrophysical Observatory of the Russian Academy of Sciences in Zelenchuk district of the Karachay-Cherkess Autonomous Area. © Oleg Makarov