How to calculate the astronomical calendar in the Spring and Autumn Period?

During the Spring and Autumn Period, with the development of productive forces, science and technology have also been improved, such as astronomy and calendars, and at this time there have been great breakthroughs. The initial system of astronomy in China was established in this period.

In ancient times, due to the need of agricultural development and political power, rulers always attached great importance to the development of astronomy. Not only did the Zhou royal family have full-time staff to legislate astronomy, but other vassal States also had full-time staff to legislate astronomy, and many famous astronomers appeared, such as Zi Shen of Lu, Bu Yan of Jin and Song.

astrology

Years of war and frequent floods and droughts are the portrayal of the Spring and Autumn Period. Natural and man-made disasters make it difficult for people to live a stable and peaceful life. In this case, people have to rely on astrology to seek some psychological comfort, which also created the ability of early astronomers as astrologers. By observing and studying the astronomical phenomena through astrology, they can not only predict the trajectory of the five stars, but also predict the occurrence time of solar and lunar eclipses. This series of actions has played a very good role in accumulating astronomical data and revealing the movement of celestial bodies.

The book Spring and Autumn Annals records many astronomical observations during this period. For example, it recorded the earliest total solar eclipse in Lu Yingong on February 22, 720 BC, while the record in the west was 135 years later. The earliest meteorite record was in the 16th year. Meteorites in Wu Song? . The earliest record of Lyra meteor shower in the world can be found in Zuo Zhuan? In summer and April, the stars are gone at night, and the stars fall like rain at night? (In the seventh year of Zhuang Gong, that is, in March 687 BC, 16).

With the further development of astronomy, on the basis of sufficient astronomical data accumulation, an astrological coordinate system represented by 28 stars was established in this period. The astrology along the celestial equator or near the ecliptic is divided into 28 different parts, each part is a night, from which 28 stars come. The order is as follows: Seven Hostels in the East (Black Dragon): Angle, Sound, Oblique, Space, Heart, Tail and Basket; Seven nights in the north (Xuanwu): fighting, cattle, women, empty, dangerous, houses, walls; Seven West Hosts (White Tiger): Kui, Lou, Stomach, Chang, Bi, Gou, Shen; Seven Nights in the South (Suzaku): Well, ghosts, willows, stars, Zhang, wings and birds. In addition, the Book of Songs, Summer and other books also recorded the names of some stars.

Zhao Gongnian of Zuo Zhuan:? Yesterday, Gao Xin's family had two sons, Job Yanbo and Yue Jishi. Move to Shangqiu, the main day. Businessmen are careers, so Chen is the star of careers; Xia Qian Shi Shen, the main ginseng. Tang people are the cause of serving Xia and Shang Dynasties. ? The ginseng and Chen mentioned here refer to the two constellations of Shang and Shen. It can be seen from this record that people at that time had a more general understanding of the knowledge of the stars. At that time, three elements, four images and twenty-eight stars were commonly used astrology, and this is how the astrological system in ancient China was formed and developed.

During this period, when observing the laws of celestial bodies, people also got some theories about the origin, structure and evolution of the universe, which laid a good foundation for the later development of astronomy.

Ancient calendar

In addition to astronomy, the calendar in the Spring and Autumn Period has also developed greatly.

The ancient calendars in China are very rich, including the arrangement of big and small months, solar terms, the number of days in each month and many other contents. The main purpose of setting up a calendar is to cultivate and facilitate people's daily production activities. Therefore, whether the conversion of solar terms can be calculated accurately and regularly is an important criterion for evaluating the quality of a calendar.

China's calendar in the Spring and Autumn Period is very advanced and at the leading level in the world. Appeared in the late spring and autumn period? Quarterly calendar? , is an important representative of this period.

Quarterly calendar? It is a calendar that takes 365 1/4 as the length of a tropic year and adds 7 leap months to 19 lunar year. What needs to be pointed out here is that the ancient calendar in China began with a combination of yin and yang, that is, the solar calendar and the lunar calendar were used together.

The so-called solar calendar is a calendar based on the movement cycle of the sun; The so-called lunar calendar, also called lunar calendar, is a calendar based on the change of the moon's full and short periods.

The year when the sun moves is called the tropic year, and the cycle of the first lunar month of the moon is the first lunar month. One of the most difficult problems in the lunar calendar adopted by China is how to arrange leap months.

The length of a tropical year is more than 365 days, while the length of a lunar month is more than 29 days, so it takes great wisdom to design a calendar accurately. The monthly light is divided into 29 days and 30 days, so1February light is 354 days or 355 days, and the length of a tropical year is 10 to1day. So there will be a difference of more than one full moon between three years. By summing up experience, the ancients gradually discovered the method of inserting leap moon.

If a leap month is inserted every three years, the lunar calendar will be a few days less than the solar calendar; If three leap months are inserted in eight years, the lunar calendar will be a few days longer than the solar calendar, which is not very accurate in short.

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After years of accumulation, people finally found a way to add seven leap months to the lunar calendar 19, which is almost equal to the number of days in the solar calendar 19.

According to Zuo Zhuan, Lu made two winter surveys in the first month of Xinhai in five years (655 BC) and in February of 20 years (522 BC). These two winter solstice days are separated by 133 years. From this, it can be inferred that Lu began to set up the calendar with 19 lunar year plus 7 leap months.

Although in the spring and autumn period, our country has not worked out a calendar with regular changes, but? Quarterly calendar? The emergence of the spring and autumn period is enough to show people's superb wisdom, and? Quarterly calendar? This method of adding seven leap months in lunar calendar 19 has also been continued by later generations, which is an important crystallization of the wisdom of the ancient people in China.