PINGTANG, July 3, 2016 (Xinhua) -- The last triangular panel to the reflector of the Five-hundred-meter Aperture Spherical Telescope (FAST) is being installed in Pingtang County, southwest China's Guizhou Province, July 3, 2016. Installation was completed on the world's largest radio telescope on Sunday morning as the last of 4,450 panels was fitted into the center of the big dish. Scientists will then begin debugging and trial observation of the FAST. (Xinhua/Liu Xu)