What kinds of calendars are there?

As can be seen from the above description, the calendar is the product of human beings entering the farming and animal husbandry society. Of course, it is difficult to prove which nation made the first calendar in the world, but every nation and country has made its own calendar since writing. However, if we analyze all kinds of calendars used in ancient and modern times, it is not difficult to find that no matter how they are renovated, there are essentially only three kinds, namely, lunar calendar, solar calendar and yin-yang calendar. Now introduce them separately.

traditional Chinese calendar

The lunar calendar is based on the change of the moon phase (that is, the new moon). Because the ancients called the moon lunar, the lunar calendar is also called lunar calendar.

It has been pointed out in the section of the first month of the lunar calendar that the average length of a first month of the lunar calendar is about 29.5306 days (equivalent to 29 days 12 hours, 44 minutes and 3 seconds), so such complicated figures are of course inconvenient to use. In order to simplify the problem and apply it, it is necessary to make every month of the calendar (called calendar month) contain only integer days. Then the integers close to 29.5306 are obviously only 9 and 30. If 29H is taken as 1 month, it will be about half a day shorter than the first month of the lunar calendar, which will inevitably lead to such disadvantages in the use process, that is, the new moon (that is, the new moon) of each month is gradually delayed; However, if the calendar month is 30 days, it is about half a day longer than the new moon, and in the process of use, the new moon will advance month by month. After a long time, there will be confusion at the beginning and end of a month. In order to make the average length of a calendar month equal to that of Wang Shuoyue, and to make a calendar month only contain the number of whole days, ancient chroniclers used four days and thirty days alternately as the length of a calendar month. This method is really ingenious, which not only avoids the complexity, but also ensures that the new moon will occur on the first day of each month.

The problem of the length of calendar months has been solved, and the calendar year (that is, the age adopted in the calendar) is the second problem that calendar jurists must solve. Calendarists will naturally consider that the length of the Gregorian calendar year should be as close as possible to the length of the tropic year, because this can truly reflect the changes in spring, summer, autumn and winter. According to this principle, after repeated observation, it is found that the cumulative days of 12 lunar month are closest to the days of the Tropic of Cancer. Look at the facts:

29.5 (day) × 1 1=324.5 (day) is about 4 1 day less than that in the tropics.

29.5 (day) × 12=354 (day) is less than that in the tropics 1 1 day.

29.5 (days) × 13=383.5 (days) is about 18 days more than the tropic of cancer.

In this way, the chroniclers set the calendar year of the lunar calendar as 12 months, including 6 big months. Abortion (30th of each month) for 6 times (29th of each month) for 354 days. But there is still a problem, because the actual length of the first month of the lunar calendar is 29.5306 days, while the actual length of the lunar year is 29.5306 (days) × 12 = 354.5438+0 (days), which is 0.3635438+0 compared with 354 days. So when it is actually used, it is a new moon every three years. In order to overcome this phenomenon, February 29th of the third year of 12 was changed to 30th, which is called leap year. There are 7 big months and 5 small months in leap year, with a total of 355 days.

As a calendar, the lunar calendar is not in harmony with agricultural production and people's daily life, so in today's world, except for a few Islamic countries that are still in use for religious reasons, other countries have generally abandoned it. Of course, from the perspective of historical development, the lunar calendar still has its own characteristics. For example, the basic cycle of the lunar calendar-the new moon-is the cycle of moon phase change. The date of the lunar calendar indicates a certain moon phase: that is, the first day is the new moon (new moon); The fifteenth and sixteenth are full moons (looking); The seventh and eighth days are the first quarter moon; Twenty-two and twenty-three are the first quarter moon and so on. It is very convenient for the ancients to judge the date by the moon phase.

solar calendar

The solar calendar is compiled according to the movement of the sun, and its basic cycle is the Tropic of Cancer. This means that a year in the Gregorian calendar is based on the tropic year, but it is not simply the length of the tropic year as the length of the Gregorian calendar year. Why? Because the length of a tropical year is 365.2422 days (equivalent to 365 days, 5 hours, 48 minutes and 46 seconds), if it is directly used as the calendar length of the solar calendar, the following phenomena will appear: for example, 1979 starts from 65438+ 10/midnight and ends at 1 midnight. It was delayed for 5 hours, 48 minutes and 46 seconds, that is, 65438+1 October1day at 5: 48: 46 am 1980. 198 1 year, starting from11/am, 37 minutes and 32 seconds. By analogy, it is very inconvenient to use. For the sake of simplicity and application, calendar experts only take the number of days in the tropical year (that is, 365 days) as the length of the calendar year, which is called the average year. Perhaps readers will ask, will it be abandoned after 5 hours, 48 minutes and 46 seconds? Of course not. The extra 5 hours, 48 minutes and 46 seconds over the years is 23 hours 15 minutes and 4 seconds, which is almost equal to 1 day. So 1 is made, that is, every four years, it will be counted as 1 day, which is called 366 days. Four years plus 1 day has another problem, that is, it is 44 minutes and 56 seconds longer than the actual length of the tropic year. At first glance, this number seems small, but don't forget the famous saying "many a mickle makes a mickle". As long as you do a concrete calculation, you will find that 400 years is three days short! Obviously, such a big error cannot be ignored. After careful consideration and calculation, the chronicler came up with the second trick: every 100 years, leap less 1 time, and leap again in the first year. After this regulation, there are 97 leap years every 400 years, and the average length of 365 days is 5: 49: 12 seconds, which is only 26 seconds different from the length of the tropic year, and the cumulative difference in 3300 years is only 1 day, which shows that the accuracy is very high.

At this point, the reader may ask again, 400 years is a leap of 4 years, and 97 years is a leap. How do you know which year is a normal year and which year is a leap year? This problem is easy to solve. Specifically, all years divisible by 4 (such as 1964, 1972, 1980) are leap years, and years divisible by 4 (such as 1979,198/kloc-)

The above is the Gregorian calendar year. How to determine the calendar month of the solar calendar?

As we all know, the number of calendar months in the solar calendar is 12 months, but this method has nothing to do with the lunar calendar. It just inherits the lunar calendar and divides a year into 12 months. According to the average distribution method, the length of calendar month should be (365.2422÷ 12=)30.4368 days. In order to avoid decimals, the calendar months of the solar calendar are also divided into big months and small months, with big months of 365,438+0 days and small months of 30 days. In normal years, there are 7 big months and 5 small months. There are six big months and six small months in a leap year. Perhaps you have noticed that the calendar months of the international Gregorian calendar are: 1, 3, 5, 7, 8, 10,1February is a big month, and 3 1 day; April, June, September,165438+1October are 30 days of abortion; Only February has 28 days in a normal year and 29 days in a leap year. What's the secret of this uneven arrangement? Why is February so special, special? It takes a long time to clarify this question, because it involves the origin of the solar calendar.

The Gregorian calendar (Gregorian calendar), which is now used internationally, originated in ancient Rome. It is said that the earliest calendar used in ancient Rome was 1 year divided into 10 month, and the year divided into 304 days. Later, due to the influence of the Greek calendar, it increased from 18 months to 12 months, with 354 days a year, which was shorter than the tropical year 1 1 many days. In order to eliminate the difference and make the calendar date consistent with the festival, it is stipulated to increase 1 month every two years, which is called leap month. The leap month is only 22 or 23 days, so it should be put in the right place. However, monks, the ruling class of the Roman Empire, abused their power and inserted leap months at will. As a result, the calendar is extremely chaotic, even the cold and heat are reversed, and the four seasons are also chaotic. Therefore, someone once said humorously and sarcastically, "Romans often win battles, but they don't know when to win them." This unimaginable chaos did not end until Julius Caesar, the Roman consul (supreme ruler), announced the new calendar in 46 BC.

Julius Caesar designed a new calendar with the help of Egyptian astronomer Sosichini. The new calendar does not consider the change of the moon at all, but only takes the period of the earth around the sun as the criterion, so it is already a pure solar calendar. Because the new calendar was promulgated by Julius Caesar, it is also called "julian calendar".

Julian calendar stipulates that the whole year is divided into 12 months, and * * * is 365 days. Every four years, the big month is 3 1 day and the small month is 30 days, so the whole year is 366 days instead of auspicious days, so 1 day needs to be removed. From which month should 1 day be deleted? It is said that in ancient Rome, all people sentenced to death were executed in February, so people thought it was an unpleasant month and hoped it would pass quickly, so 1 day was subtracted from February, so there were only 9 days in February and 30 days in leap year. As for February becoming 28 days, there is another story.

According to legend, Julius Caesar's birthday is in July, which is the big month, so he often takes pride in it and boasts of his extraordinary. Unexpectedly, Julius Caesar was assassinated in 1 year after the calendar change. After his nephew Octavian succeeded to the throne in 27 BC, he became the supreme ruler of Rome and enjoyed the reputation of Augustus (Augustus means "sacred" and was the honorific title of the Romans at that time). Unfortunately, the rule of "leap three years" stipulated by Julius Caesar has always been misunderstood by monks as "leap three years", so the leap year has been set as many as 12 times from the time when it was set in 42 BC to the time when it was set again in 9 BC. There are three leap years more than the original regulations. Fortunately, Augustus woke up from a rude awakening and found that the present leap method was a misunderstanding of julian calendar, so he decisively announced that there would be no leap from 8 BC to 4 AD. Julius Caesar's scientific rule of "leap every three years" was re-implemented in the eighth year after AD. From this point of view, Augustus has set things right. However, he took credit for it and got carried away. He abused his power, adding 65,438+0 days from February to August, the month when he was born, and boasted that he had supreme dignity, comparable to Julius Caesar. Since then, August has become 3 1 day, February has become 28 days, and leap years have only 29 days. Since August, it has been changed to a big moon. Since August, it is simply that every pair is a big moon and every order is a small moon.

The average calendar year length of "julian calendar" is 365 days and 6 hours (that is, 365.25 days), which is shorter than the regression time 1 1 min 14 seconds. For more than three days in 400 years, it can be seen that "julian calendar" needs to be further improved. In A.D. 1582, Pope Gregory XIII ordered the reform of the calendar. There were two measures: (1) changing 1582 10 5 to 10 6+05. (2) Those years whose century number is not divisible by 400 (such as 1700, 1800) are no longer counted as leap years. Only years in which the century number is divisible by 400 are considered as leap years, such as 1600 and 2000.

These two provisions are very important. First, after the implementation of the "julian calendar", March 2 1 was designated as the vernal equinox in 325, but by the time Gregory promulgated the new calendar in 1582, the vernal equinox had actually reached March 1 1, which was 10 days less than the specified date. The first measure of the new calendar eliminated this contradiction. The vernal equinox returned to March 2 1 stipulated in 325 AD. Second, the second move of the new calendar changes the rule that julian calendar has 100 leap years in 400 years to 97 leap years in 400 years, so that the average age of the new calendar is ([365× 400+97] ÷ 400 =) 365.2425 days, only 0.0003 days older than the return. It can be seen that it took more than 3300 years for the new calendar to have a one-day error. Compared with "julian calendar", the new calendar has undoubtedly made great progress. This new calendar is called the Gregorian calendar. Because of its accuracy, it is gradually adopted by countries all over the world, so the Gregorian calendar is now the universal Gregorian calendar, also known as the solar calendar. China adopted the Gregorian calendar in 19 12 years after the Revolution of 1911. See Table 4 for the time when other countries adopted the Gregorian calendar.

In the process of introducing the origin of the Gregorian calendar, readers may have a question, that is, the Gregorian calendar was published and implemented in A.D. 1582, so how was the "A.D." in the Gregorian calendar era determined?

Era is the starting point of the recording era. Different times and countries have different chronologies. In ancient China, the so-called "chronology of the throne" was adopted, that is, 1 year when an emperor ascended the throne was 1 year, followed by the second and third years ... After the emperor was replaced, the chronology began again. For example, Kangxi ascended the throne in the Qing Dynasty in 1662, so 1662 was called the first year of Kangxi, and 1663 was the second year of Kangxi, and so on. In the areas controlled by the Roman Empire in Western Europe, the chronology is similar to that in ancient China (just like the beginning of the chronology when Diocletian, the Roman ruler, proclaimed himself emperor), or "Rome was founded" as the beginning of the chronology (it is difficult to verify the founding date of Rome). /kloc-In the 20th century, Christianity rose in Europe, with increasing power and influence. After the so-called "Rome was founded" in 1284, there was a very talented Christian monk, De Onisi, who suggested that Christians should not use the "foreign" chronology, but should change it to 1 year as the year of the birth of Christ. According to him, Christ was born 532 years ago, so the next 1 year should be 533 years after the birth of Christ. This new chronology was first used in the church, and by the middle of15th century, it was widely used in the proclamation issued by the Pope. When Gregory promulgated the new calendar in 1582, this chronology was already used as a habit, so the worldwide calendar began in 532, not in 1 year. The first year of A.D. is equivalent to the first year of Yuan Dynasty of Emperor Han Ping of China.

As for the beginning of the Gregorian calendar, it is artificial. The earth goes round and round the sun, with no beginning and no end. People deliberately set a starting point as the beginning of a year. According to the ancient custom, the day after beginning of winter 10 to Sunday (the day with the lowest sun height at noon) is chosen as New Year's Day (65438+ 10/). I used it later.

lunisolar calendar

On newspaper mastheads and calendars, besides the year, month, day and day of the Gregorian calendar, there are also the year, month, day and solar terms of the lunar calendar. The lunar calendar here is the combined calendar of yin and yang to be discussed in this section.

From before Qin and Han Dynasties to the end of Qing Dynasty, there were more than 100 kinds of famous calendars in China, all of which belonged to the lunar calendar. It is said that our ancestors used this calendar as early as the Xia Dynasty (before17th century BC), so people also called it the "summer calendar". After liberation, it was still called "Summer Calendar", and after 1970, it was renamed "Lunar Calendar" in China newspapers. As for the origin of the name "Lunar Calendar", it is probably because China has been based on agriculture since ancient times, and the calendar must serve agriculture.

As we all know, the basic cycle of the lunar calendar is the new moon, and the basic cycle of the solar calendar is the tropic of cancer. The combination of yin and yang, as the name implies, is a calendar that takes into account both the solar calendar and the lunar calendar. Furthermore, the lunar calendar takes the time for the moon to orbit the earth once (that is, the first month of the lunar calendar) as one month, and the time for the earth to orbit the sun once (that is, the tropic year) as one year. The uniqueness of this calendar is that the date of the calendar month represents a certain moon phase, such as the first new moon and the full moon in the middle of the month; On the other hand, it is in harmony with spring, summer, autumn and winter. However, the biggest difficulty in making lunar calendar is that there is no common denominator between lunar month and tropic year, so it is most reasonable to arrange several months in a year, which has become an urgent problem for chroniclers.

The calendar year of the lunar calendar is based on the tropic year, but 1 tropic year is 365.2422 days, which is about 1 1 day more than 12 = 354.3672 days. If every year is 12 months, it will cause confusion when accumulated. For example, the Spring Festival of 1980 is in February, and the Spring Festival of 1996 after 16 is in August. How inconvenient! In practice, the ancients thought that 1 year was about 1 1 day, and three years was 33 days, so it was stipulated to add 1 month every three years, which was called leap year. Although this is a big step forward on the road to solving the problem, the problem is not completely solved. In the long years, after careful observation and calculation, our ancestors discovered the "seven leap years method of 19", that is, seven leap years are set in 19 (leap years are every year 13 months), and the rest 12 years are average years (every year/kloc) With this ingenious method, the length of 19 calendar year and 19 tropic year is almost the same. Please see the specific calculation:

1 month =29.5306 (days)

12× 19+7=235 (full moon)

235 months =29.5306×235=6939.69 (days)

1 tropical year =365.2422 (days)

19 tropical year =365.2422× 19=6939.60 (days)

The calculation results show that the difference between 19 tropic year and 235 lunar months is only 0.09 days (2 hours, 9 minutes and 36 seconds). Obviously, this discovery is a great leap in the history of China! It harmonizes the lunar calendar with the solar calendar better, and the order of seasons and months of the calendar is basically in line with the actual weather. By the way, this law was first discovered by ancient astronomers in China. When the Greek discovered this cycle, China had successfully used 160 years.

During the Southern and Northern Dynasties, Zu Chongzhi, an outstanding mathematician and astronomer in China, made an innovative Da Ming Calendar in the sixth year of Daming (AD 462), which created a more accurate method of "39 1 year 144 leap" than "19 leap", that is, in 3965438.

When introducing the "lunar calendar", I should remind you that it is wrong for some people to call it the lunar calendar. The principles of three calendars are introduced here. Let's review that the lunar calendar is only related to the movement of the moon, while the lunar calendar takes into account the basic characteristics of the solar calendar and the lunar calendar. It has similarities and differences with the lunar calendar in principle, so it can't be called the lunar calendar. As for the lunar calendar, it is called the old calendar, which is probably relative to the Gregorian calendar. Because our country has adopted the lunar calendar since ancient times, and after the Revolution of 1911, 19 12 adopted the Gregorian calendar, people used to call the Gregorian calendar the "new calendar". In contrast, the lunar calendar is naturally called the old calendar, so the names of the new calendar and the old calendar are just habits.

As can be seen from the above, the success of the combined calendar of Yin and Yang lies in the clever setting of leap months, but why sometimes leap in March, sometimes leap in May and sometimes leap in August? This is a problem closely related to the 24 solar terms.