Photo taken on June 27, 2016 shows the Five-hundred-meter Aperture Spherical Telescope (FAST) under the stars in Pingtang County, southwest China's Guizhou Province. The China-based FAST, the world's largest single-dish radio telescope, has identified two pulsars after one year of trial operation, the National Astronomical Observatories of China (NAOC) said on Oct. 10, 2017. Photo: Xinhua

Staff members work in the control room of the Five-hundred-meter Aperture Spherical Telescope (FAST) in Pingtang County, southwest China's Guizhou Province, Aug. 9, 2017. The China-based FAST, the world's largest single-dish radio telescope, has identified two pulsars after one year of trial operation, the National Astronomical Observatories of China (NAOC) said on Oct. 10, 2017. Photo: Xinhua

Staff members work in the feedback source cabin of the Five-hundred-meter Aperture Spherical Telescope (FAST) in Pingtang County, southwest China's Guizhou Province, Aug. 10, 2017. The China-based FAST, the world's largest single-dish radio telescope, has identified two pulsars after one year of trial operation, the National Astronomical Observatories of China (NAOC) said on Oct. 10, 2017.Photo: Xinhua

Staff members work in the feedback source cabin of the Five-hundred-meter Aperture Spherical Telescope (FAST) in Pingtang County, southwest China's Guizhou Province, Aug. 10, 2017. The China-based FAST, the world's largest single-dish radio telescope, has identified two pulsars after one year of trial operation, the National Astronomical Observatories of China (NAOC) said on Oct. 10, 2017.Photo: Xinhua