Ancient Chinese Sky Viewer

The ancient Chinese were very great astronomers; they kept incredibly accurate records of the stars, eclipses, and many other astronomical events. They even recorded the appearance and disappearance of "guest stars," which were things like comets and other bright objects that appeared in the sky. These records enabled us to figure out the occurence of the Crab Nebula supernova in 1054.

Some of the best Chinese records are amazingly detailed star charts, like the one shown above. It is a picture of the Suchow planisphere, created in A.D. 1193. It was designed by a man named Huang Shang, who was a great geographer and teacher in the Emperor's court. It was eventually carved into stone by Wang Chih-Yuan in A.D. 1247. The actual planisphere is quite large.

The planisphere divides the sky into 28 slices, called hsiu by the Chinese. Literally translated, hsiu means "lunar mansion." Each of these hsiu track the location of the moon in the sky, and are given the name of their associated constellation. Most of the hsiu were also correlated with important events that occured in the circumpolar region, a very important region of the sky to the Chinese; in this region of the sky, the stars never set.

Each of the hsiu are described in the above applet; their corresponding constellations are highlighted, and the most important events of the circumpolar region are described. Furthermore, the hsiu were divided into four groups of seven, which are assigned a season, color, and animal; these are shown on the above applet as well.

Also important on the Suchow planisphere are the large circular regions. The smallest of these outlines the circumpolar region, described above. The other two are the celestial equator and the ecliptic, described on the planisphere as the "Red Road" and the "Yellow Road," respectively. According to the planisphere's accompanying text, the "Red Road encircles the heart of heaven, and is used to record the degrees of the twenty-eight hsiu." The "Yellow Road," or the ecliptic, is the path of the sun through the night sky. Finally, the planisphere discusses the "White Road," or the path of the moon; it gives an accurate description of lunar and solar eclipses.

These are the most important attributes of the planisphere, and the only ones detailed in the above applet. However, it is interesting to note that there are 1565 named stars on this planisphere!

For more information about Chinese astronomy or the Suchow planisphere, see Joseph Needham's Science and Civilisation in China, vol 1 or Star Charts and Moon Stations.