This aerial photo taken on Feb. 13, 2023 shows China's Five-hundred-meter Aperture Spherical Radio Telescope (FAST) under maintenance in southwest China's Guizhou Province. FAST, the world's largest single-dish radio telescope, has identified over 740 pulsars since its launch, the research team has announced. Dubbed as the "China Sky Eye," the telescope is located in a naturally deep and round karst depression in the southwestern province of Guizhou. It has a reception area equal to 30 standard football fields. (Xinhua/Ou Dongqu)