(FAST; Chinese: 五百米口径球面射电望远镜), nicknamed Tianyan (天眼, lit. "Heavenly Eye") is a radio telescope located in the Dawodang depression (大窝凼洼地), in Pingtang County, Guizhou Province, southwest China. (中國貴州省平塘縣克度鎮)
It consists of a fixed 500 m (1,600 ft) diameter dish constructed in a natural depression in the landscape. It is the world's largest filled-aperture radio telescope.
The 500 meter-diameter telescope, which will dwarf the 300 meter-diameter Arecibo Observatory in Puerto Rico furthers China's technological clout.
The telescope is made up of 4,450 triangular-shaped panels. It has a novel design, using an active surface made of metal panels that can be tilted by a computer to help change the focus to different areas of the sky.
The cabin containing the feed antenna suspended on cables above the dish is also moved using a digitally-controlled winch by the computer control system to steer the instrument to receive from different directions. It is currently undergoing testing and commissioning. It observes at wavelengths of 10 cm to 4.3 m.
The telescope made its first discovery of two new pulsars in August 2017, barely 1 year after its first light. The new pulsars PSR J1859-01 and PSR J1931-02, which are also referred to as FAST pulsar #1 and #2 (FP1 and FP2), were detected on August 22 and 25 and are 16,000 and 4,100 light years away, respectively.
On 26 December 2008, a foundation laying ceremony was held on the construction site.Construction started in March 2011, and the last panel was installed on the morning of 3 July 2016. Originally budgeted for CN¥700 million, the final cost was CN¥1.2 billion (US$180 million).
Its working frequency range of 70 MHz to 3.0 GHz,with the upper limit set by the precision with which the primary can approximate a parabola.
