Book of Astronomy

In the ninth month of autumn, on the day of Guihai original: 癸亥 (guǐhài). The 60th day in the traditional Chinese sexagenary cycle used for dating..

The Emperor presided at the

original: 奉天門 (Fèngtiān Mén). The main ceremonial gate of the imperial palace where the Emperor conducted daily administrative business.. He summoned his officials from the Hanlin Academy original: 翰林 (Hànlín). The elite imperial institution composed of the empire's highest-ranking scholars., Li Chong and Wu Bozong, and addressed them, saying:

"The Way of Heaven is profound and subtle, revealing signs in the heavens to provide guidance to humanity. A sovereign must embody the patterns of Heaven and carry out the Way; only then is the merit of governance achieved. The kings and emperors of antiquity looked up to observe the celestial patterns and down to examine the geography of the earth, using this knowledge to refine human affairs and nurture all living things. From these practices, written records flourished, and the moral order original: 彞倫 (yílún). The constant ethical principles and social norms that govern human relationships. was properly arranged.

Recently, the cosmologists original: 陰陽家 (yīnyáng jiā). Literally "Yin-Yang specialists"; here the Emperor refers to the Islamic astronomers and mathematicians from the West. of the Western Regions original: 西域 (Xīyù). A term for Central and Western Asia, including the Persian and Arabic-speaking worlds. have been predicting celestial phenomena with extreme precision. They possess methods for verifying latitudes original: 緯度 (wěidù). While it means latitude today, here it refers to the specific Islamic astronomical calculations of planetary positions and coordinates. that are not fully detailed in Chinese books. Since this is of great significance to the relationship between Heaven and humanity, it is fitting that their books be translated, so that they may be studied from time to time."