Later, the delegation and Liang Lingzan designed and manufactured the water elephant. This kind of hydraulic elephant, with a time-telling device, can automatically tell the time, which is called the top view of water-borne turbid days or Kaiyuan water-borne turbid days. A group of people observed the movements of the sun, the moon and the five stars with the newly-made zodiac navigator, and measured the equatorial coordinates of some stars and their relative positions with the ecliptic. It was found that the positions of these stars changed greatly from those measured in the Han Dynasty.
Since the twelfth year of Kaiyuan, a group of people have presided over large-scale national astronomical geodesy, among which a group of observations made by Nangong Shuo and others in Henan Province are the most successful. They measured the height of the local North Pole, the length of the summer solstice shadow and the distance between the four places in Henan today. After a row of calculations, it is concluded that the height difference of the North Pole is one degree, and the distance between north and south is 35 1 m, with 80 steps. This is actually to find out the length of the earth's meridian.
The Dayan calendar was drawn up in the 13th year of Kaiyuan, and a calendar was compiled. After two years, I wrote a draft and named it "Da Yan Li". His party died at the age of 45. After the publication of Da Yan Li, Zhang Shuo and Li Guan Chen compiled it into a book.
Since the 17th year of Kaiyuan, calendars compiled according to Dayan calendar have been issued nationwide. After testing, Dayan Calendar is more accurate than other calendars in the Tang Dynasty. It has been nearly a hundred years since Kaiyuan was introduced to Japan in the 21st year.
His party Taoism is profound, clever and alert since childhood, and he is proficient in classics and history. He often goes to Du Xuan Temple in the south of Chang 'an, which is rich in books and appreciated by the viewer Yin Chong.
On one occasion, he borrowed Yang Xiong's Xuan Jing from Yin Chong. This book is of profound significance. Yin Chong claimed to have studied it for several years and could not understand it. It took him only a few days to finish it, and he was able to write a volume of Yan Xuan Tu. Yin Chong was shocked and told people that Yan Zi was born after that. This young group has become a famous scholar in Chang 'an.
Wu Sansi, the nephew at that time, was appointed as the official of Spring Festival travel rush. He admired the knowledge and behavior of his party very much and appointed him King Liang. Wu Sansi is very powerful, but he has no talent. His party disdained to associate with him, so he went to Songshan to become a monk and took a dharma name.
Zhao Feng formulated a new calendar, which not only had profound insights into Taoism, but also assiduously studied astronomy and mathematics. He went to Guosi Temple in Tiantai Mountain to study arithmetic. In the fifth year of Kaiyuan, his party was forced back to Beijing by the Tang Dynasty. Because he didn't want to be an official, he was placed in Huayan Temple in Chang 'an to compile Buddhist scriptures. In the ninth year of Kaiyuan, the frequent solar eclipse of Taishi was invalid. The Lin Xin calendar used at that time has been used for more than 50 years, and the error is getting bigger and bigger, so it is necessary to reform the calendar. Therefore, the imperial edict line is responsible for the formulation of the new calendar.
The party is committed to this work. From the ninth year of Kaiyuan to the fifteenth year of Kaiyuan, a great deal of astronomical observation work was carried out under the leadership of the Party in order to compile a new calendar.
In order to meet the needs of practical measurement, the team cooperated with Liang Lingzan, a machinery manufacturer, to create some new scientific instruments, such as torque repeater, ecliptic instrument and water elephant.
On the basis of mastering a large number of measured data, the line re-measured the positions of more than 50 stars in/kloc-0, and found that the positions of these stars recorded in ancient books did not match the actual positions. He discovered the phenomenon of star motion for the first time, which was 17 12 years earlier than the idea of star motion put forward by British astronomer Harley.
Great contributions to science are mainly in three aspects: astronomical instrument manufacturing, geodesy and the compilation of Dayan calendar. In particular, Dayan Calendar was the most accurate calendar at that time, and it was a great achievement at that time, which was praised by the world.
Xing Hepu, a Taoist priest, praised his party and said: Luo Zuoli in the Han Dynasty said,' At the age of 800, there must be a saint.' The year has passed, and it is a mistake to make a great calendar. What if you believe what you say instead of being a saint? It can be seen that people's contribution to the line at that time was very respectful. Together with Liang Lingzan and others, the delegation also designed and manufactured the Huntian bronze instrument, which is powered by water power and engraved with the sun, the moon and the stars, rotating once a day and night, in line with the astronomical phenomena. What's even more amazing is that there are two Woodenhead in the instrument, one is to beat the drum all the time, and the other is to ring the bell every hour, which can be automatic on time. Huntian Copper Instrument is not only an astronomical instrument, but also the earliest timer with mechanical rotation in the world. In the step-by-step technique of Da Yan Li, a line set up a table for each shadow length from 0 to 80 degrees corresponding to the zenith distance of the sun, which is the earliest tangent function table in the history of mathematics in the world.