Because the difference between Yin and Yang calendars is about 1 1 day every year, and three years is about 1 month. In order to adapt this calendar to the cycle of hot and cold weather changes, it is stipulated that 1 leap month is added every two or three years, and 7 leap months are set every 19 years. 19 is a leap chapter, 8 1 chapter is unified, and 3 chapters are unified into one yuan, each yuan is 46 17 years, and the yuan is repeated.
The lunar calendar has a long history of more than 3,000 years in China. China knew as early as the Yellow Emperor that 1 has 365.25 days, 1 has 29 days, and a year has 12 months. On this basis, six ancient calendars of China were compiled: Huangdi, Zhuan Xu, Xia, Yin, Zhou and Lu. For example, in 2009, China adopted the method of 65438+7 leap, which was hundreds of years earlier than that of Greece. It can be seen that the ancient calendar in China is very advanced. At the end of the Western Han Dynasty, the three calendars changed by Liu Xin according to Deng Ping's taichu calendar, the Daming Calendar compiled by Zu Chongzhi in the southern Qi Dynasty and the Yuan Calendar compiled by Fu in the Tang Dynasty are all famous yin and yang calendars.
The Yin-Yang calendar has been revised by calendar experts in past dynasties and is still in use in China. It is closely related to agriculture, and many familiar solar terms and agricultural proverbs are based on it, so people also call it the lunar calendar.
The real lunar calendar has long been abolished in the world, but in our country, the lunar calendar has been preserved in order not to break the traditional habits. This is the day of the lunar calendar printed in lowercase letters.
China's first complete calendar-Gregorian calendar
Since the Qin and Han Dynasties, there have been more than 100 kinds of ancient calendars in China. Why did successive dynasties change calendars so frequently? There is a reason for this.
As early as the Zhou Dynasty, informing the new moon was a symbol of power. In feudal society, the right to issue calendars was one of the symbols of imperial power. Changing dynasties often requires changing the year number and calendar, which is for political reasons.
The inconsistency between the eclipse and the advance is another important reason for the revision of the calendar. In the Tang Dynasty, it was a serious matter to test whether the solar eclipse forecast was accurate. In fact, the difference between solar terms is not obvious in a day or two, but the error of solar eclipse will be felt in a few minutes.
In BC 104, Chang 'an, the capital of the Han Dynasty, posted a notice to recruit astronomers to make calendars in Beijing, and then recruited more than 20 people from all over the country, including An Youqi, Luo Xiahong, Tang Dou, Gong Sunqing and Hu Ai. They discussed and formulated the taichu calendar Law, which is the first complete calendar handed down so far. Sima Qian, a famous writer and historian, also participated in the discussion of calendar formulation. Only Sima Qian's suggestion was not adopted. Probably for this reason, Sima Qian did not mention taichu calendar when he wrote Historical Records and Almanac.
Taichu calendar stipulates that the length of 1 month is 29 days, with 7 leap months in normal year 1 February, leap year1month and 19. So every year is 12 months, which is equivalent to 365 days a year. The length of year and month are the two most basic data for making calendars. Compared with modern measured values, although the error between these two figures is relatively large, it is not easy for early calendars to do this.
Luo Zeng, who was involved in calendar production at that time, said that the calendar after 800 years would be 1 day. Therefore, the early calendar is not as accurate as the quarterly calendar.
Taichu calendar was published in 104 BC (the first year of Emperor Wu of Han Dynasty), starting from the midnight winter solstice of Jiazi in that year 1 1 month, which was the result of a practical measurement. The solar term of the winter solstice is orthogonal to the first half of 1 1 month in BC, which coincides with Jiazi Festival. Taking this moment as the starting point is very beneficial to the calculation of many cycle values of the calendar. Because the starting point of the day-midnight; The starting point of January-Shuodan; The starting point of a year-11month; The starting point of the 60-year-old cadre week-Jiazi; The starting point of the twenty-four solar terms-winter solstice, the starting points of the five cycles all meet together, just as all five runners start at the starting point at this time. With this starting point, at any moment, where they go can be simply calculated through their respective cycles.
Taichu calendar has a line 188, which was replaced by the calendar of the later Han Dynasty in 84 AD.
Zu Chongzhi's Big Li Ming
After the Han Dynasty, the calendar in China developed greatly, and many good calendars appeared in Wei, Jin, Southern and Northern Dynasties, such as "Calendar at the Beginning of Scene" written by Yang Wei in the Three Kingdoms period. During the Northern and Southern Dynasties, He Chengtian's Li Yuanjia and Zu Chongzhi's Da Li Ming were both famous, especially Da Li Ming, which was more creative. Zu Chongzhi (429-500 AD), the calendar maker of Da Ming Li, was a great scientist in the history of China, who made great achievements in mathematics, mechanical manufacturing, music and so on, especially in mathematics. However, astronomical calendar is also one of the main contents of his research, and he has also made great achievements, and Daming Calendar is his representative in this respect.
Zu Chongzhi created a lot in Daming. He takes 3939 as the denominator, and the number of days in 65438+ 10 =29 days, and the decimal number is 29.53059 days, which is very close to the new moon length measured now, with a difference of less than 1 second. He thinks that the traditional value of 65438+7 leap months in 2009 is a bit too big, and the difference in 2000 will be 1 day, so he proposes a leap week of every 39 1 year 144 leap months. The accuracy of this value can be verified in the following ways:
If the leap is 65438+7 in 2009, it is 12 months per year, and the length of 1 year is: 365.2468 (days).
At present, the length of 1 tropical year is 365.2422 days, with an annual difference of 0.0046 days. So Zu Chongzhi said that there will be a gap of 1 day in 200 years. Change it to 39 1 year 144 leap, and the older is: 364.2428 (day) is only six ten thousandths of the measured value, which means that 1 year is 52 seconds, which is quite accurate.
Another innovation of Daming Calendar is to introduce the concept of precession for the first time. For the first time, Zu Chongzhi adopted the latest achievements at that time when compiling the calendar, so that the position of the winter solstice among the stars moved westward a little every year. Although the moving value is small, it has great influence. It provides us with a scientific basis for determining the historical age, and it gives us a materialistic view that the starry sky is slowly changing. The preaching of "the sky remains unchanged and the Tao remains unchanged" has no market in the Ming calendar.
The value of the intersection month was obtained by Zu Chongzhi for the first time in the history of China. The intersection month is the time when the moon crosses the intersection of ecliptic and ecliptic twice. The intersection of yellow and white is extremely important for the occurrence of solar and lunar eclipses. Eclipses only occur when the new moon or the moon appears near the intersection, so how often the moon crosses the intersection is a very important concept. The result of Zu Chongzhi is =27.2 1223, which is very close to the measured value today. This progress in Daming Calendar is of great significance to the calculation of solar and lunar eclipses.
Daming Calendar is one of the most important calendars in the history of China, and many calendars in later generations are not as accurate as it. It was used for nearly 80 years 10 year after Zu Chongzhi's death, that is, 5 10 year.
Excellent Calendar-Goose Calendar
In September of 72 1 year, people from Taishi Bureau came and went. Although everyone is busy, there is no sound, because according to Linde calendar, there will be a solar eclipse on this day, but I don't know if it is as accurate as predicted. Everyone is making preparations before observation: some are missing engravings accurately, some are preparing record books, and some are preparing oil pans.