spaceSpace and Physics

World's Largest Radio Telescope Enters Final Construction Phase


Robin Andrews

Science & Policy Writer

3963 World's Largest Radio Telescope Enters Final Construction Phase
This beast of a radio telescope is getting its finishing touches in China. NDRC/NAOC/CAS

The construction of the world’s largest radio telescope, which is being installed in China’s Guizhou province, has entered its final stage. As the name suggests, the Five hundred-meter Aperture Spherical Telescope (FAST) will use a reflector dish that is 500 meters (1,640 feet) long to look out for signals emitted from radio sources many light-years from home, as reported by Business Standard.

The last stage of construction involves the “retina,” the collecting point for the incoming radio signals. It will be installed in a cabin, a part of the telescope suspended up to 160 meters (525 feet) above a reflector made of 4,450 individual panels.


Each of these equilateral triangle-shaped panels are controlled by cables fixed to the back of it, meaning each one can adjust its angle and position in accordance with the source cabin. The entire system will be highly sensitive, with operators able to make unprecedentedly small adjustments: The maximum error will be less than 1 centimeter (0.4 inches).

“If you compare the FAST to an eye, then the feed source is its retina,” said Sun Caihong, a chief engineer with the FAST programme, as reported by Business Standard. “All signals we collect eventually come here.”

Construction has been ongoing since March 2011. Work on the reflector – a gigantic piece of equipment designed to focus the incoming radio waves into the receiving antennae – is still continuing through this final stage. Just this weekend, the 30 tonne (33.1 ton) retina cabin was successfully lifted above the reflecting dish in a particularly precarious operation.

The surrounding area is free from towns and cities within a sphere of roughly five kilometers (3.1 miles), meaning that there will be little radio wave interference for the telescope as it peers into space. Zheng Xiaonian, the deputy head of the National Astronomical Observatories under the Chinese Academy of Sciences, claims that FAST will be 10 times more sensitive than a similar observatory in Bonn, Germany.


When it eventually does come online, it will overtake Puerto Rico’s Arecibo Observatory – another radio telescope – which is 305 meters (1001 feet) in diameter. Designed to receive only radio waves, the telescope will help us study various deep space objects including supernovae and star nurseries.

Image credit: The previous record-holding radio telescope  the Arecibo Radio Telescope in Puerto Rico. Quazgaa/Wikimedia Commons; CC BY 2.0


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