Why do leap years have 366 days? How to calculate the lunar leap year?
In China, there has been a dry calendar since the Shang Dynasty, with twelve earthly branches in the Eastern Zhou Dynasty, a dry calendar in the Western Han Dynasty and a dry calendar in the Eastern Han Dynasty. Previous history books all used the system of cadres and branches.
Based on Wang Shuo in the lunar calendar, the actual length of Wang Shuoyue ranges from 29.3 days to 29.7 days, with an average of 29.588 days. According to the average value, it is called "Pingshuo" and the actual length is called "Dingshuo". Pingshuo was collected before the second year of Tang Wude (6 19), and it was set in June19. Pingshuo was used again in the 19th year of Zhenguan (645), and it was not until the 2nd year of Song Linde (665) that Dingshuo was used again.
In the first year of Emperor Taizu of Han Dynasty (BC 104), it was officially stipulated that the tropic year consisted of twenty-four solar terms, and the month without neutral atmosphere (twelve solar terms, such as winter solstice, severe cold and rain, were called neutral atmosphere) was a leap month. Before that, leap month was arranged in the last month of the year. The actual number of days in a tropical year is 365.38+079.
I. Ancient Six Calendars
This is the six calendars of Huangdi, Zhuan Xu, Xia, Yin, Zhou and Lu formulated in the Spring and Autumn Period, Warring States Period and Qin Dynasty. It is characterized by taking 365+ 1/4 (denominator is 4, so it is also called calendar) as a tropic year, and taking 29+499/940 (29.4438+0) as a tropic year. The differences between the six calendars are mainly the "era" (the starting point of a year), the implementation area and the beginning of the year. The period of use was mainly the Warring States period, but the Zhuan Xu calendar was always used until Liang Wudi changed its calendar (BC 104). Published documents: Hanshu, Annals of Law and Discipline, Kaiyuan Zhan Jing.
The first month of the year is the mid-winter month (the second month), which includes the winter solstice. It is called "Zhou Zheng".
The first month of the year is called "Andrew".
The first month of the year is Meng Chun (silver moon) month, which is called "Xia Zheng".
Zhuan Xu calendar built Hai, with Meng Dongyue (Hai Yue) as the first month of the year, which was called "Qin Zheng" in history.
In ancient times, the leap months of six calendars were all placed at the end of a year, and beginning of spring was the starting point of the solar terms in a year.
In the Spring and Autumn Period, it was used in the Jin Dynasty, in the early years of Lu Dynasty, in the first 65 1 year of Lu calendar, in the period of Xin Mang, and in the Tang Dynasty, it was used in Zetian and Suzong. Xia Zheng was adopted in other periods after Emperor Wu of the Han Dynasty.
Two. Korean (calendar, seasonal calendar, dry calendar)
Taichu calendar, which was created by Luo, Liu and others 104 years ago, is the first relatively complete calendar in the history of China and the first major reform in history. For the first time, it put the 24 solar terms into the calendar, and took the month without neutral gas as leap month; It is calculated that 135 months has 23 mating cycles. However, it was not until the first 45 years that the West formulated the julian calendar, with a tropical year of 365.25 days. Moreover, 8 years ago, a leap of 3 years was mistakenly set. In fact, 365.33 days is a year. 1 leap in the first 8 years was changed to 4 years, and the return year was 365.25 days. It was not until 1582 that the Gregorian calendar was changed, with 365.2422 days as a year.
1. Early calendar
Take 365+385/1539 (365.5438+06244) as the tropic year, and 29+43/8 1 (29.530864) as the new moon (denominator is 8 1, so it is also called eighty. Calendar (the beginning of a year): On the first day of November before the first year of Taichu (BC 104), Jiazi Day is midnight, which happens to be the new moon and the winter solstice. Published literature: History of Han Law.
2. Quarterly calendar
In the second year of Yuanhe in the Eastern Han Dynasty (85), it was changed to a quarter calendar (also known as the "quarter calendar of the later Han Dynasty" to distinguish it from the ancient six calendars). Edited by Li Fan? Made in 1985. The winter solstice is corrected, and the equatorial degree and ecliptic degree of 28 stars are determined according to the actual observation. Service life: 85-263 years. During the Three Kingdoms period, Shu used the seasonal calendar, Wei used the seasonal calendar in the early days, and later changed to the calendar at the beginning of the scene, and Wu used the dry calendar. Published documents: records of laws in the later Han Dynasty.
The calendar takes 29+499/940 (29.55438+0) as the first lunar month and 365+7/32 (365.2 1875) as the tropic year.
Step 3 dry calendar
Room Liu Hongjian 179- 184 (206? ), taking 365+145/589 (365.24617997) as the tropic year and 29+773/ 1457 (29.530542) as the first month of the lunar calendar, also recorded the knowledge of the moon movement. The year of use is 223-280, which was used by Wu during the Three Kingdoms period. Published documents: The Book of Jin, Fa and Li.
Era (the beginning of the year): Shang Yuan Chou. In the 11th year of Jian 'an, Xu Bing (206) was born in 7378.
Three. Wei (calendar, Taihe calendar, Jingchu calendar)
The calendar in the early Jin dynasty was renamed Taishi calendar, and in the Song dynasty it was renamed Yongchu calendar.
1 Huang Chu calendar
It was formulated by Hanyi (Wei) in 220, but it was not used. Published literature: Book of Jin: Annals of Law and Discipline (algorithm not introduced).
2. Taihe calendar
Gao was formulated in 227 (Wei) and was not adopted. Published literature: unknown.
3. Calendar at the beginning of the scene
Yang Wei, the state of Wei, made it in 237, with 29+24 19/4559 (29.530599) as the first lunar month and 365+402/1843 (365.5812263) as the first lunar month. Service years: 237-45 1. Published documents: Jin Law Record and Song Law Record.
Time: Shang and Chen. In the first year of Jingchu, Ding Si (237) was 4046 years old.
When sixteen countries entered Jin, some countries used the calendar at the beginning of the scene. In the Northern and Southern Dynasties, the early calendar of Jing was used in the Southern Dynasty.