Gregorian, Gregorian and Gregorian calendars

Gregorian calendar = Gregorian calendar = Gregorian calendar

At present, the calendars used all over the world are called Gregorian calendar, which is essentially solar calendar.

The original solar calendar was founded by the ancient Egyptians. At first, a year was considered as 365 days. In order to coordinate the length of the calendar year and the tropic year, Julius Caesar, the Roman ruler, revised the solar calendar and formulated the julian calendar in 46 BC. In the 8th year BC, Augustus, Caesar's nephew, adjusted julian calendar. Julian calendar divides a year into twelve months, with an average of 365 days; Leap years divisible by 4 total 366 days. In this way, the average length of julian calendar over the years is 365.25 days, which is 0.7078 days different from that of the Tropic of Cancer (365.2422 days) and about 3 days different in 400 years. From the implementation in julian calendar to the end of16th century, the cumulative difference was about10th day. In order to eliminate this difference, Pope Gregory XIII set julian calendar1the second day of October 4th 1582 10 as15, and eliminated the middle 10 day; At the same time, the leap year rules in julian calendar are modified: the year divisible by 4 is still a leap year, but for century years (such as 1600, 1700, ...), only the year divisible by 400 is a leap year. In this way, there are only 97 leap years in 400 years, three less than the original, making the average length of the calendar year 365.2425 days, which is closer to the length of the tropic year. After this modification, julian calendar was called the Gregorian calendar, also known as the Gregorian calendar. The Gregorian calendar was first used in Catholic countries and was widely adopted around the world at the beginning of the twentieth century, so it is also called the Gregorian calendar. China adopted the Gregorian calendar in 19 12, but it still uses the year of the Republic of China. 1949 After the establishment of People's Republic of China (PRC), the Gregorian calendar was adopted.

Lunar calendar = lunar calendar = summer calendar

The lunar calendar, also known as the Xia calendar, is said to have originated in the Xia Dynasty in China. It is very scientific and practical, so it has been passed down to this day. The lunar calendar is divided into four seasons, twenty-four solar terms and annual festivals according to the natural days of the whole year. The twenty-four solar terms of the lunar calendar include: beginning of spring, rain, fright, vernal equinox, Qingming and Grain Rain; Summer is long, full, busy, midsummer solstice, light summer heat and great summer heat; Beginning of autumn, Chushu, Bailu, Autumnal Equinox, Cold Dew and Early Autumn Frost; Beginning of winter, light snow, heavy snow, winter solstice, slight cold and severe winter cold. In addition, the months in the whole year are set according to the cycle of the moon phase change. That is, the big month is 30 days and the small month is 29 days. The first day of each month in the lunar calendar is called "New Moon" and the fifteenth day of each month is called "Wang". On the "new moon" day, the moon moves between the sun and the earth, and the shadow faces the earth and appears at the same time as the sun, so people can't see the moon. On lookout day, the earth moves between the sun and the moon. The sun sets in the west and the moon rises in the east, so we can see the full moon. Because the lunar year is about 355 days, which is about 1 1 day different from the earth year, there should be a leap month every 3 years and 7 leap months every 19 years. A year with a leap month is also called a leap year. The specific leap month depends on the elasticity of solar terms.

The lunar calendar is designated not only according to the time spent in the year of the return of the earth, but also according to the changes of the moon phases, and with reference to the surrounding meteorological and phenological conditions and agricultural activities, so it becomes a calendar with four distinct seasons and easy to remember. In China, the lunar calendar is especially suitable for the vast areas of the Central Plains.