What is the relationship between monks and meridian?

Monks in the Tang Dynasty in China and their entourage were the first astronomers to measure meridian in the world.

Monks and their entourage (A.D. 673-727) were surnamed Zhang before they became monks, and were called Agali and Julu (now Hebei) in history. He is the grandson of Xiangzhou satrap and Yong Gongzhang in the early Tang Dynasty. Since childhood, I love studying and reading widely, especially studying astronomy and calendars. When he was young, he was more fearless and diligent. 2 1 year-old became a monk with Jing Zen master in Jingzhou, and soon learned Zen with Puji in Songshan. Later, he also learned the secret method from Sumitomo Buddha and King Kong Zhi.

Monks and his party are proficient in Buddhism, calendar, mathematics and astronomy. During the Kaiyuan period of the Tang Dynasty (AD 7 13-74 1), Xuanzong of the Tang Dynasty recruited scholars and celebrities to Beijing. He was called to Chang 'an to be with his uncle and doctor Zhang Qia. Since then, he has been immersed in astronomical observation and calendar reform until his life. In the 15th year of Kaiyuan (AD 727), a group of people were ordered to compile Great Yan Li, which was relatively advanced at that time. Mathematically, he invented the inequality interval quadratic difference interpolation formula, and wrote 20 volumes of The Great Sun Classic and Multiplication, Adjustment and Storage.

Together with Liang Lingzan, he also made the Huntian Bronze Instrument (an ancient instrument for measuring celestial sphere coordinates) and the Zodiac Navigator, and redefined the position of 150 star. He found that the data obtained from the coordinates of the star equator (the celestial equator, the great circle where the equatorial plane of the earth intersects the celestial sphere) and the relative position of the ecliptic (the great circle where the orbital plane of the earth intersects the celestial sphere) are very different from those obtained from previous astronomical measurements, and their positions on the ecliptic are also different. From this, the monk and his party came to the conclusion that stars are not static, but also moving.

17 18, British astronomer Harley also put forward the viewpoint of star motion according to the difference between the ecliptic of stars and that of ancient Greece. However, this was nearly 1000 years later than the discovery of a line.

The greatest contribution of the monk and his party in astronomy is that he first measured the length of the meridian (the imaginary line connecting the north and south poles through a certain point on the ground).

In the 12th year of Kaiyuan in the Tang Dynasty (AD 724), under the initiative and leadership of monks and their party, a large-scale astronomical survey was conducted in cooperation with Nangong Shuo, the astronomical calendar officer of Taishijian in the Tang Dynasty. The measurement contents include the length of the sun shadow of the eight-foot pole at noon on the vernal equinox, summer solstice, autumn equinox and winter solstice, the height of the North Pole and the length of day and night. There are as many as 13 measuring points. From Tiele in the north (now northern Inner Mongolia) to Lin Yi in the south (now central Vietnam). The height of the North Pole and the length of the sun shadow in Huazhou (now hua county, Henan), Junyi (now Kaifeng), Fugou and Shangcai were emphatically measured, and the distance between these four places was also measured. Results From Huazhou to Shangcai, the height difference of the North Pole is 1.5 degrees, the distance between the north and the south is 526 Li and 270 steps (300 steps in the Tang Dynasty is one Li), and the difference between the summer solstice and the sun shadow is more than 2 inches. The calculation results show that the height difference of the North Pole is 1 degree, and the distance between north and south is 350 Li and 80 steps, that is, 15 1? 07 kilometers. Although this result is not very accurate, it is a great progress in method, and it is also the first time in the world to measure meridians on such a large scale.

The earliest meridian measurement abroad was carried out by Arab astronomer Al-Pritzker and others. They measured the meridian of Mesopotamia in August14, nearly 90 years later than our country.

Monks and his party were well-known scientists in ancient times and made great achievements.