In addition to the compilation of Xiao Tong mentioned above, the Zhang was given great honors in life and in death. The former masters regarded the Sun as round like a crossbow bullet, and they thought the Moon had the nature of a mirror. His uncompromising stance on historical and calendrical issues led to his becoming a controversial figure, preventing him from rising to the status of Grand Historian. Educated in the capital cities of Luoyang and Chang'an, he achieved success as an astronomer, mathematician, seismologist, hydraulic engineer, inventor, geographer, cartographer, ethnographer, artist, poet, philosopher, politician, and literary scholar.
The planets (as well as the Moon) have the nature of water and reflect light. The circle of the ecliptic also goes round the belly of the instrument at an angle of 24 (degrees) with the equator. Thus at the summer solstice the ecliptic is 67 (degrees) and a fraction away from the pole, while at the winter solstice it is 115 (degrees) and a fraction away. When (a similar effect) happens with a planet (we call it) an occultation; when the Moon passes across (the Sun's path) then there is a solar eclipse.Zhang Heng viewed these astronomical phenomena in supernatural terms as well. Thus the moon's brightness is produced from the radiance of the Sun, and the Moon's darkness is due to (the light of) the sun being obstructed. On the covers of each (inflow receiver) there are small cast statuettes in gilt bronze; the left (night) one is an immortal and the right (day) one is a policeman. But any cause coming upon it from without rouses it, or compresses it, and drives it into a narrow space ... and when opportunity of escape is cut off, then 'With deep murmur of the Mountain it roars around the barriers', which after long battering it dislodges and tosses on high, growing more fierce the stronger the obstacle with which it has contended.In 132, Zhang Heng presented to the Han court what many historians consider to be his most impressive invention, the first seismoscope. The water dripping (from above) enters two inflow receivers (alternately), the left one being for the night and the right one for the day. His rhapsody "Sir Based-On-Nothing" provides details on terrain, palaces, hunting parks, markets, and prominent buildings of Zhang wrote about the various love affairs of emperors dissatisfied with the imperial harem, going out into the city incognito to seek out prostitutes and sing-song girls. The former figure is adopted only because it agrees with the (results obtained by the) method of measuring solstitial sun shadows as embodied in the Xia (dynasty) calendar.Zhang Heng's water-powered armillary sphere had profound effects on Chinese astronomy and mechanical engineering in later generations. As long as it is not stirred, but lurks in a vacant space, it reposes innocently, giving no trouble to objects around it. The side which faces the Sun is fully lit, and the side which is away from it is dark. The philosopher and poet In honor of Zhang's achievements in science and technology, his friend Cui Ziyu (Cui Yuan) wrote a memorial inscription on his burial stele, which has been preserved in the Several things have been named after Zhang in modern times, including the lunar crater "Zhang Heng" in Traditional (top) and Simplified (bottom) Chinese charactersNeedham (1986), Volume 4, Part 2, 484; Needham (1986), Volume 3, 632.Needham (1986), Volume 3, 538. Zhang Heng (Chinese: 張衡; AD 78–139), formerly romanized as Chang Heng, was a Chinese polymathic scientist and statesman from Nanyang who lived during the Han dynasty. Those parts of the Moon which the Sun illuminates look bright, those parts which it does not, remain dark.The theory posited by Zhang and Jing was supported by later pre-modern scientists such as Bronze vessels are made and placed one above the other at different levels; they are filled with pure water. His political rivalry with the palace Zhang applied his extensive knowledge of mechanics and gears in several of his inventions. "the title may have referred to a Bird's Eye Map ... that Chang Heng occupied himself with map-making is sure ... a physical geograph map was presented by him"Cutter (1984), 11 (footnote 61), 15, (footnote 80), 26 (footnote 141). But now (it has been recorded that) the spring equinox is 90 and 1/4 (degrees) away from the pole, and the autumn equinox is 92 and 1/4 (degrees) away. Eventually, he became Chief Astronomer, Prefect of the Majors for Official Carriages, and then Palace Attendant at the imperial court. Some of them recognized the Moon as a ball too. Zhang Heng began his career as a minor civil servant in Nanyang. This was seen as a general criticism of the Eastern Han emperors and their imperial favorites, guised in the criticism of earlier Western Han emperors.The Sun is like fire and the Moon like water. The chief tradition leading to Yi Xing (AD 725 ) was of course the succession of 'pre-clocks' which had started with Zhang Heng about 125. Hence (the points) where the ecliptic and the equator intersect should give the north polar distances of the spring and autumn equinoxes.
The light pouring forth from the Sun does not always reach the moon owing to the obstruction of the earth itself—this is called 'an-xu', a lunar eclipse. These figures guide the indicator-rod (lit.