A worker installs reflector panels of the single-aperture spherical telescope "FAST" in Pingtang County, southwest China's Guizhou Province, March 9, 2016. A total of 3,492 reflector panels, an equilateral triangle with a side length of 11 meters each, have been installed on the frame. 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)