Book of Astronomy

...[the Emperor’s] command. We were most reverent. An office was opened to the right of the Right Shun Gate original: 右順門 (Yòushùn mén). The "Gate of Right Filial Obedience," located in the Forbidden City, where officials often met for imperial business.. Together, we engaged in mutual study and refinement original: 切劘 (qiēmó). Literally "cutting and polishing," a metaphor for scholarly collaboration and rigorous debate. to reach the original meaning of the texts, not daring to add or subtract even a hair’s breadth.

In the second month of the following year, the translation of the astronomical books was completed. They were transcribed and presented to the Emperor. There was an imperial decree commanding your servant Zhou Ziyi to write a preface.

Your servant has heard that:

• Fuxi The first of the Three Sovereigns of ancient China, credited with creating the Eight Trigrams. drew the Eight Trigrams;
• Yao of Tang A legendary sage-king noted for his piety and for commissioning astronomical observations. reverently observed the celestial phenomena;
• The Great Shun regulated the Seven Regulators Seven Regulators original: 七政 (qīzhèng). Refers to the Sun, the Moon, and the five visible planets: Mercury, Venus, Mars, Jupiter, and Saturn.;
• The Divine Yu categorized the Nine Domains original: 九疇 (jiǔchóu). The fundamental principles of governance and natural law found in the "Great Plan" of the Classic of History..

These traditions have been passed down through the dynasties, and the written records have become increasingly comprehensive. They speak of the transformations of Heaven and Earth, the opening and closing of Yin and Yang original: 闔闢 (hépì). A philosophical term for the alternating cycles of the universe., the movement of the sun, moon, and stars, and the succession of cold, heat, day, and night. When coupled with the fortunes of human affairs and the growth and decay of physical laws, these matters are indeed subtle, profound, and expansive.

Now, observing the Western Regions original: 西域 (Xīyù). While historically referring to Central Asia, in the late Ming context it often referred to Europe (Great West)....