Halley's Comet and the Ganshi Classic of the Constellations
The Chinese people have paid great attention to astronomical phenomena since very early times. Meteor showers and solar eclipses which occurred as far back as in the Xia Dynasty are recorded in ancient books, and are thought to be the earliest astronomical accounts. By the Spring and Autumn and Warring States periods, astronomy had reached quite a high level of sophistication. Astronomers of the State of Lu observed 37 solar eclipses, among which 33 have been proved accurate. The earliest record of an appearance by Halley's Comet (613 BC) is contained in the chronicle of Lu known as the Spring and Autumn Annals.
During this period there appeared specialized works on astronomy. Gan De of the State of Qi wrote a work titled Astronomy and Astrology in eight volumes, and Shi Shen of the State of Wei wrote his Astronomy, also in eight volumes. Later, the two works were combined as the Ganshi Classic of the Constellations. The earliest astronomical work extant in the world, it records the motions of Mercury, Jupiter, Venus, Mars and Saturn. There also recorded the names of 800 stars, the positions of 121 of which have been ascertained. Gan De discovered Jupiter's moon with the naked eye, 2,000 years earlier than the Italian astronomer Galileo, who discovered it with an astronomical telescope in 1609. Shi Shen discovered the reason for solar and lunar eclipses. A crater on the moon has been named after Shi Shen.