Photo taken on Aug. 2, 2015 shows an aerial view of the assembly site of the single-aperture spherical telescope "FAST" in Qiannan of southwest China's Guizhou Province. The assembly of the reflectors on the telescope, with a dish the size of 30 football fields and located deep in the mountains of Guizhou, has entered a key stage as workers began hoisting the first reflector here Sunday. When it is completed in 2016, the five hundred meter aperture spherical telescope (FAST) will be the world's largest, overtaking Puerto Rico's Arecibo Observatory, which is 300 meters in diameter. (Xinhua/Ou Dongqu)