Da Tang Kaiyuan zhan jing

Da Tang kai yuan zhan jing is a Chinese astrology encyclopedia, compiled by imperial order by numerous scholars around 718-724, during the Kaiyuan era of the Tang dynasty. The work was led by Gautama Siddha (flourished in the 8th century), the Tang-dynasty astronomer and astrologer of Indian descent, who was born in Chang'an. The book, also known as the Kaiyuan Star Observations, contained approximately 600,000 words in 120 juan. The compilation was based on many astronomical, astrological, and divination materials from prior to the Tang dynasty. In particular, it incorporated many fragmentary works and works no longer extant from Shi Shen, Gan De (included in juan 23), and Wu Xian, from the Spring and Autumn period and the Warring States period (770--221 BCE), such as the three star charts made by Gan De. It also includes the translation of the astronomical table of sine by the Indian mathematician and astronomer, Aryabhata (born 950), which shows early signs of international interaction by astronomers. By the tenth century, copies of the manuscript began to disappear. It was said that around 1616--17 scholar Cheng Mingshan found a copy of the work in the stomach of an old Buddha sculpture. Earlier works were in 110 juan, but this copy has 120 juan, with the last ten juan containing information on grasses, trees, animals, and human- and animal-shaped vessels, which could have been added later. The work begins with a discussion of the structure of heaven and Earth, discusses divinations relating to heaven, Earth, sun, moon, the five stars, 28 constellations; stars, such as meteors, parasitic stars, nova and comets, guest stars, and shooting stars; wind, clouds, rainbows, frost and snow, and thunder. Most importantly, the work collected the results of the observations, theories, and prognostications of earlier astronomers and astrologers prior to the Tang dynasty.