Li is from Yong. His father Li Bo used to be a local official. "Disappointed with his official position, he abandoned his official position and became a Taoist priest." Li Bo "has a lot of documents, and he named himself Huangguanzi, annotated it, wrote ten volumes of Local Records, and wrote Astronomical Elephant Fu. These undoubtedly had a certain influence on Li Yisheng's academic orientation. In Old Tang Book, it is said that Li is "young and handsome, rich in books, especially good at studying Yin and Yang".

As early as the early years of Zhenguan (A.D. 627-649), Li made his mark in the Li Tang period, which was due to his astronomical attainments. The calendar used in the early Tang Dynasty was Fu's Five Tones Yuan Calendar, which had some defects. Li made a detailed study of this, put forward suggestions for revision, and sent people to inspect it and adopted some of his suggestions. In ancient times, calendar compilation was a specialized subject, which was difficult for ordinary scholars to ask. However, when Li was in his twenties, he put forward some suggestions on the revision of Wuyin Yuanli, which naturally attracted people's attention. He was also praised for this, was awarded a general, and entered the Taishi Bureau to start his career as an official astronomer.

Biography of Li in Old Tang Dynasty: Li was born in Yong (now Qishan Town, Fengxiang, Shaanxi Province) in the second year of Sui Renshou (AD 602). His father Li Bo was a small official in the county government during the Sui Dynasty. He was a low-ranking Taoist and gave up his official position. He is quite learned, named Huang Guanzi, with a note. Therefore, under the influence of his father Li, he was known as a "prodigy" from an early age, especially fond of astronomy, geography, Taoism and the study of Yin and Yang. At the age of 9, he went to Jingyun Temple in Nantuo Mountain, Henan Province to worship Yuan Daochang as a teacher. /kloc-returned to his hometown at the age of 0/7, was recommended by his friend Liu Wenjing, and became a counselor to take part in the uprising against Sui and Xing Tang. In 6 18, the emperor was made king of Qin, and Li Shenjun became the minister of Qin. In the first year of Tang Zhenguan (627), Li took the assistant minister directly to Taishi Museum. In the Taishi Museum, which is in charge of astronomy, geography, calendars and the compilation of historical books, Li fully demonstrated his talent and devoted himself to it for 40 years.

achievement

1. He improved the astronomical armillary sphere invented by Luo in Han Dynasty, and added the three rings of ecliptic, equator and white road (called the instrument in ancient times) to make astronomical observation more convenient and accurate. It was the most advanced astronomical observation instrument in the world at that time. All the weapons made after the Tang Dynasty are modeled after this structure, and now the ancient weapons copied by Nanjing Purple Mountain Observatory are also modeled after this structure.

2. Zhou Pian Jing and Gu Shi Jing, presided over by Zhao and annotated by Dr. Guo Xue and Wang Zhenru, assistant professor of imperial academy, were awarded national textbooks, which were the earliest mathematics textbooks in the world and had a great and far-reaching influence on oriental mathematics in later generations. China, Japan, Korea, Viet Nam and other countries have been used until modern times. Dr Needham called it "the greatest mathematical work in the whole history of China".

At the age of 3.25, he wrote a letter to improve the five-tone yuan calendar, personally presided over the expert review, and finally adopted seven suggestions.

4. When compiling Jin Shu Tian, he summed up that the tail of a comet "refers to the east in the evening, and refers to the west in the morning", which often turns away from the sun, more than 900 years earlier than the west. Known as the "treasure house of astronomical knowledge", it has a far-reaching impact on the development of astronomy in later generations.

He collected the astronomical observation and calculation results of nearly 40 years and compiled the Linde Calendar, which became his masterpiece in Taishi Bureau, and the artist called it Precision.

6. During his seclusion in Feng Chun Village, he observed the wind with his own "three-legged chicken weathervane", which was rated as Grade 8, thus becoming the first ancient scientist in the world to classify the wind. After 65,438+0,000 years, European talents refined it into 13 wind on the basis of the 8-level wind set by Li.

Li not only made great achievements in scientific practice, but also made great achievements in writing books: