Zhang Heng (AD 78- 139), a native of Xi 'e, Nanyang (now Shiqiaoxia Village, Nanyang City, Henan Province), once held the posts of Shangshu and Hejian. He is "intelligent, sensitive and eager to learn, like the death of Sichuan, sleepless." Morality is overflowing, articles are floating clouds, mathematics is poor in the world, production is natural, skills are extraordinary, and aboveboard. "He" is not disrespectful, and he is disrespectful of virtue; ""I'm not ashamed of Lu's incompetence, but of my ignorance. "He was a great scientist, writer, inventor and politician in the Eastern Han Dynasty in China, and set up a towering monument in the history of world science and culture.
Shi Shen, a native of Shishenfu, wei ren, was an astronomer and astrologer in the mid-Warring States period. The year of birth and death is unknown, and he lived in the 4th century BC.
According to the official "Tian Guan Shu", there were four famous astronomers in the Warring States Period: "Qi Zhong, Gan Gong; Chu,; Zhao,; Wei, Shi Shen. " It is also said that the astronomy of various factions has the content of astrology. In their works, we can see the situation of war and mutual search at that time, and record various statements about political events, that is, "the fields are compiled, and the three factions are divided into Jin, which is the Warring States Period." In the battle for prisoners, the war became more intense and several cities were massacred. Because of hunger, the priest is very worried, and he is particularly eager to see the stars. In modern times, twelve kings and seven kingdoms were kings, and the speakers followed suit from the vertical, while Gao, Tang, Gan and Shi discussed books on current affairs, so they occupied miscellaneous rice and salt. "Justice in Historical Records" quoted the Southern Dynasties Liang's "Seven Records" as saying: "During the Warring States Period, stone gods wrote eight volumes of astronomy. "Unfortunately, this book has been lost.
Stone God's contribution to astronomy is that he and Gander measured and accurately recorded the positions of the stars near the ecliptic and their distances from the North Pole. This is the oldest catalogue in the world. According to legend, he measured 138 and ***880 stars. Judging from part of the works of stone gods in Tang Dynasty preserved by Zhan Jing in Kaiyuan, the most important thing is the coordinate position of 12 1 star marked "Stone Moon" (this edition of Six Lost Stars by Zhan Jing in Kaiyuan). Modern astronomers have verified some coordinate values (such as the extremes of officials in the stone and the external and internal degrees of the ecliptic) according to the calculation of astronomical phenomena in different periods. ) It may have been measured in the Han Dynasty. Another part (such as the distance of twenty-eight nights, etc. ) is indeed consistent with the era in the 4th century BC, that is, the Story of the Stone.
Guo Shoujing (1231-1316) was a great astronomer, mathematician, water conservancy expert and instrument manufacturer in Yuan Dynasty. Think about the word, you are from Xingtai, Shunde (now Xingtai, Hebei). He was born in Yuan Taizong for three years and died in Yuan Renzong for two years.
Guo Shoujing studied astronomy, mathematics and water conservancy under his grandfather Guo. In 13th year of Yuan Dynasty (AD 1276), Kublai Khan of Yuan Shizu captured Lin 'an, the capital of Southern Song Dynasty. On the eve of reunification, he ordered the establishment of a new calendar, and Zhang Wenqian and others presided over the establishment of a new institution-Taishi Museum. Wang Xun is in charge of Taishi Bureau, assisted by Guo Shoujing. Academically, Wang Xun is responsible for calculation, while Guo is responsible for making instruments and observing.
In the 15th (or 16th) year of Zhiyuan, Taishi Bureau was renamed Taishi Museum, Wang Xun was appointed Taishi Order, and Guo Shoujing set up an observatory for Zhitai History Museum. At that time, Yang Gongyi and others came to * * *. After four years of hard work, a new calendar was finally compiled in the seventeenth year of Zhiyuan, which was named Chronological Calendar by Kublai Khan.
Zu Chongzhi (AD 429-500) was born in Laiyuan County, Hebei Province during the Northern and Southern Dynasties. He read many books on astronomy and mathematics since childhood, studied hard and practiced hard, and finally made him an outstanding mathematician and astronomer in ancient China.
Zu Chongzhi's outstanding achievement in mathematics is about the calculation of pi. Before the Qin and Han Dynasties, people used "the diameter of three weeks a week" as pi, which was called "Gubi". Later, it was found that the error of Gubi was too large, and the pi should be "the diameter of a circle is greater than the diameter of three weeks". However, there are different opinions on how much is left. Until the Three Kingdoms period, Liu Hui put forward a scientific method to calculate pi-"secant" which approximated the circumference of a circle with the circumference inscribed by a regular polygon. Liu Hui calculated the circle inscribed with a 96-sided polygon and got π=3. 14, and pointed out that the more sides inscribed with a regular polygon, the more accurate the π value obtained. On the basis of predecessors' achievements, Zu Chongzhi devoted himself to research and repeated calculations. It is found that π is between 3. 14 15926 and 3. 14 15927, and the approximate value in the form of π fraction is obtained as the reduction rate and density rate, where the six decimal places are 3. 14 1929.