Zhang Heng

In his youth, Zhang Heng was a writer and famous satirical book about the manners of high society. At the age of 30 engaged in astronomy / astrology. Consisted of State. service, twice served as chief historian of the court, was the chief astrologer to the Emperor An of Han (107 - 125 gg.), in his later years was a minister of the ruler inheritance Hejian. In 123 g. made correction calendar.

Zhang Heng - creator of the armillary sphere (celestial globe), driving the water truck, a compass, a sundial, the device for recording tremors (invented in 132 g.). The founder of quantitative cartography, based on a rectangular grid coordinates. He divided the sky in the constellation 124, and 320 gave the names of the stars. Zhang Heng was the first in China concluded that the Moon shines by reflected light from the sun, and correctly explained the phenomenon of lunar eclipses. All lights Zhang Heng believed spheric. He defined the angle of inclination of the ecliptic to the celestial equator (24 DU, ie. 23.671 б°), calculated the number pi (3.04132). We proceed from the geocentric views of the universe, identified universal spiritual and material substance (Qi) with water, in which "float" Heaven and Earth. Assumptions about infinity and the unknowability of the universe, a huge duration of the process cosmogenesis. Defining different categories of celestial bodies, pointed to the existence of the 2500 "current stars" and 11520 "secret stars" (number 11520 - the product of numerology "Canon of Changes", symbolizing the entire "dark things"). Speed of movement of celestial bodies in the sky tied to their distance from the Earth. Opposed the practice of divination by mantic books, denied the story of the origin of the practice of the ancient "sovershennomudryh" rulers.

In honor of Zhang Heng named lunar crater Chang Heng.