Ancient Observatory (Guguanxiangtai)

A passer-by strolling east of Tiananmen Square in the middle of Beijing will be surprised to see an ancient observatory high up on the top of a fort-like building at Jianguo Gate. From the avenue below, some of the various archaic instruments are clearly visible in the skyline, standing as anachronistic reminders of Imperial Beijing. This ancient pre-telescopic observatory, the most important in China, was built in 1422 atop a city wall, soon after an earlier observatory in Nanjing.

On entering the unassuming entrance of the observatory compound, one can see various sea-faring instruments at the courtyard, including an interesting sundial that caught the interest of Prof. M.L. Pei in the design of additional concentric rings. One then enters a two storey museum which is a collection of pictures, write-ups and busts to show the ancient Chinese scientists and their various astronomical achievements. An impressive replica of a Ming Dynasty gold foil map of the constellations can be seen in the museum.

On climbing to the roof of the museum, one is privy to the unique giant bronze instruments that one could see from the street below. There are only eight in number and they were designed in the Qing Dynasty with such classy names as celestial globe, dragon quadrant, ecliptical armilla and azimuth theodolite. Some of these were left-over from the Jesuits. As there were originally more than these eight instruments, some of them were stolen by the Germans and French during the invasion of Beijing by the Eight Nations' Allied Forces in 1900. Following persistent outcry by the Chinese, they were returned to China after the World War 1. In 1931, some of the more ancient instruments were sent to the Nanjing to evade the invading Japanese. Those in Nanjing are at the Purple Mountain Observatory Museum and the Nanjing Museum.

It was said that following the fall of the Northern Song Dynasty 1227, the victorious Jins transferred the ancient astronomical instruments from Kaifeng to the first observatory in Beijing. in. 1279, the succeeding invading Mongols under Kublai Khan built the second observatory in Beijing just north of the present observatory. With the fall of the Mongols, Zhu Yuanzhang, the founding Ming Emperor, transferred the instruments from Beijing to Nanjing. When the Yongle Emperor ursurped the throne from his nephew, he did not dare to transfer the instruments to Beijing out of respect for his father who was buried in Nanjing. Instead he commissioned craftsmen to make wooden models of these instruments and had them cast in bronze, including the armillary sphere, the abridged armilla and the Yuan guibiao sundial.

With the completion of the present observatory in 1422, it has housed the replica instruments and served the Ming and Qing astronomers in their star-gazing reports, for the Emperor, the Son of Heaven, is closely tied up with the movements of the heavenly bodies. Another function is to assist sea navigation, and apparently Muslim scholars were also recruited for this expertise. In the seventeenth century, the Jesuits, who were able to more accurately predict the eclipses, helped to further develop the observations of the stars and the planets.

An interesting fact is that the ancient Chinese were able to measure with accuracy the positions of stars and planets in the 1400s without the telescope. The various astronomical instruments and their names can be seen at the website and

Beijing Planetarium