This scene shows the panorama of the 500-meter Aperture Spherical Telescope in Pingtang county, Guizhou province, Sept 24, 2016. [Photo/Xinhua]

A launch ceremony was held in Pingtang County, Guizhou, for the Five-hundred-meter Aperture Spherical Telescope (FAST).

FAST, also called "China's eye of heaven," is the world's largest and most sensitive radio telescope, and China holds the intellectual property rights to it, Xi said in the letter.

Its launch is significant for China to achieve major breakthroughs in frontier scientific fields and to expedite innovation-driven growth, Xi said, adding astronomy is crucial to propelling scientific progress and innovation.

Xi called on scientists, engineers and builders to manage the telescope well and wished them fruitful research. He said he hopes they can make new and greater contributions to building China into an innovative country and a global science power.

Vice Premier Liu Yandong, who read the letter at the launch ceremony, urged efforts to pool top-notch talent, boost international cooperation, and make FAST a high-end scientific research platform.

Liu called on scientists to strive for significant and original discoveries and elevate Chinese astronomy to a world-class level.

FAST's tasks include survey of neutral hydrogen in the space, observation of pulsars as well as spacecraft tracking and communications.

Work on the project started in 2011. The installation of the telescope's main structure -- a 4,450-panel reflector as large as 30 football pitches -- was finished in early July.