Photo taken on Dec. 16, 2015 shows the assembly site of the single-aperture spherical telescope "FAST" in Pingtang County, southwest China's Guizhou Province. A total of 2,059 reflector panels have been installed. Each panel is an equilateral triangle with a side length of 11 meters, and has cables fixed to the back of it so that it could adjust angles and positions in synchronization with the source cabin, which is driven by cables, servomechanisms in additional to a parallel robot as a secondary adjustable system. (Photo: Xinhua/Ou Dongqu)
