Situated at the southeast corner of Jianguomen Bridge, it was initially built circa 1442, during the Ming Dynasty (1368-1644). Its rich history spans more than five hundred years, making it one of the most historically interesting observatories in the world. During the Ming Dynasty it was known as the 'Platform of Star-Watching', but its name was later changed to 'Observatory' during the Qing Dynasty (1616-1911). After the Revolution of 1911, the title became 'Central Observatory'. It was renovated in the early 1980s and reopened to the public in 1983. Today, it has become the 'Ancient Astronomical Instruments Display Hall', an affiliate of the Beijing Observatory.
In total, it covers an area of 1,000 square meters (about 0.25 acre). It is divided into two parts, the platform and the affiliated building. The platform is 17.79 meters (about 58.4 feet) high, 24 meters (about 78.7 feet) long and 20 meters (about 65.6 feet) wide. Eight bronzed astronomical instruments stand on this platform, all of which are ornately carved, having been well preserved since the time of the Qing Dynasty. They are huge but exquisitely carved. The design of the instruments reflects both the influence of Oriental craftsmanship and European Renaissance understanding of measurements and physics. Under the platform stands a group of affiliated buildings, built with simple elegance. It is a milestone in Chinese architecture, marking a cultural exchange between the Orient and the West. It is not only a place to observe the heaven but a unique historical treasure.