Chinese Astronomy

Introduction

Chinese scholars began by thinking of the stars, the sun, and the moon as gods. But by the time of the Han Dynasty, about 130 AD, scholars like Zhang Heng knew that the moon was a sphere, lighted by the sun on one side and dark on the side away from the sun. Zhang Heng also understood what caused solar and lunar eclipses. Chinese astronomers, like Roman and Sassanian astronomers of the same time period in Europe and West Asia, were very interested in the stars both for scientific reasons and because they believed that the skies could help predict the future. But Chinese astronomy was much more advanced than our Western one and they progressed much quicker than us.

The purpose of astronomy in the past

One of the main functions was for the purpose of timekeeping. The Chinese used a “luni-solar” calendar, but, because the cycles of the sun and the moon are different, leap days, weeks and even months had to be inserted into the calendar.

The Chinese calendars were considered to be a symbol of a dynasty. As dynasties would rise and fall, astronomers and astrologers of each period would often prepare a new calendar to be made, with observations for that purpose.

Ancient Chinese astronomers divided the stars into “fixed stars” and “guest stars”.  The supernova that created the “Crab Nebula” observed in 1054 (now known as the SN 1054) is an example of a “guest star” observed by Chinese astronomers, although it was not recorded by their European contemporaries.

Models of the Heavens

The Chinese developed three different cosmological models. The Gai Tan, or hemispherical dome, model conceived the heavens as a hemisphere lying over a dome-shaped earth. The second cosmological model, associated with the Hun Tian School, saw the heavens as a celestial sphere not unlike the spherical models developed by the Greeks. The third model, associated with the Xuan Ye School, viewed the heavens as infinite in size and the stars as floating spheres of light passing the Earth at rare intervals, and as they said: "the speed of the luminaries depends on their individual natures, which shows they are not attached to anything." The Xuan Ye School was right about the size, but the “luminaries”, as they called them, do not move “on their individual natures”, but it is the Earth that moves.

Constellations

Chinese constellations are the groupings used by the ancient Chinese to organize the stars. They are very different from the modern constellations. This is because the modern ones were based on Greco-Roman astronomy instead of Chinese astronomy.

Ancient Chinese “sky-watchers” divided their night sky into 31 regions: the Three Enclosures and the Twenty-Eight Mansions. The Three Enclosures occupy the area close to the North Celestial Pole. The stars in the Three Enclosures can be seen all year around. The Twenty-Eight Mansions occupy the “zodiacal band”. These find their equivalent in the 28 lunar mansions of western astrology. Though marked along the zodiac, they are defined by the movement of the Moon rather than the Sun.

The Chinese Constellations are:

·         The Purple Forbidden Enclosure

·         The Supreme Palace Enclosure

·         The Heavenly Market Enclosure

·         Virgo

·         Libra

·         Scorpios

·         Sagittarius

·         Capricorn

·         Aquarius

·         Aries

·         Taurus

·         Gemini

·         Cancer

·         Spica

·         Antares

·         Aquarius/Pegasus

·         Pegasus

·         Andromeda

·         Pleiades

·         Orion

·         Hydra

·         Alphard

·         Crater

·         Corvus

·         Aries

·         Sagittarius

·         Corvus

·         Orion

·         Pegasus

·         Aquarius

·         Libra