GUIYANG, Sept. 18 (Xinhua) -- China has issued a commemorative stamp in honor of the world's largest radio telescope, located in the southwestern province of Guizhou.

The State Post Bureau (SPB) has issued a set of five stamps, including one commemorating the Five-hundred-meter Aperture Spherical radio Telescope (FAST) with a value of 1.2 yuan (0.18 U.S. dollars).

The other four stamps honor China's quantum science experimental satellite "Mozi," the research vessel Tansuo-1, a national grain production project around the Bohai Sea and the Sunway TaihuLight supercomputer.

With an investment of 1.2 billion yuan, FAST is a single-dish telescope with a diameter of half a kilometer. It was built in the Dawodang depression, a natural karst basin in Pingtang County in mountainous Guizhou. The telescope is designed to probe space for the faintest signs of life and is sensitive to any electromagnetic interference.

Surrounding areas are open to visitors. But the number of visitors is strictly controlled below 2,000 people per day and electronic devices including cell phones and cameras are prohibited.

Since it began operation in September last year, it has received 240,000 visitors, according to local authorities.