Which is better, the twelve calendars or the Gregorian calendar?

Later generations think that Shen Kuo's twelve-year calendar is more scientific and ideal than the Gregorian calendar we use today. For example, the first year of the Gregorian calendar (New Year) has no astronomical significance, but beginning of spring in the first year has astronomical significance. The second is that there will be a maximum difference of three days between months in the Gregorian calendar, and the arrangement of large months and small months is irregular. However, only the difference between the big moon and the small moon is 1 day, which is arranged regularly.

But the annual apparent motion of the sun is actually uneven, and the uneven motion of the sun was discovered in the Northern Qi Dynasty in the 6th century. One-day tour is later after vernal equinox and faster after autumnal equinox. Therefore, starting from 1645, the ecliptic period (360) starts from the winter solstice and is divided into 24 equal parts. In this way, the position of the sun in each solar term is fixed, and the included angle between two adjacent solar terms is 15, but the time interval is not equal. This method is called constant gas method. Today, the calendar we commonly use also adopts the method of constant gas.

If we copy the calendar of 12 years now, there will be an imbalance between May with 32 days and 165438+ 10 with only 29 days.

Of course, in order to meet the balance of calendar months, it is still possible to alternate large and small months, and it is still possible to ensure that most solar terms are at the beginning and middle of each month.

Take 20 12 years as an example, one month is small and two months are big. In a normal year, 65438+February becomes a small moon.

Beginning of spring 65438+1 October 1 Rain 65438+1October1June, February1Spring Equinox February 16 Qingming February 3 1 Grain Rain March.

April 1 long summer is full, April 16 awn seed, May 17 summer solstice, June 3 summer heat, June 18 summer heat.

Beginning of autumn has dew in the summer of July 3rd, July 19, August 4th, autumn equinox of August 19, cold dew on September 4th, and early frost on September 6th, 19.

Beginning of winter 65438+1light snow 65438+1heavy snow 65438+1winter solstice 65438+1slight cold 65438+February 2+great cold 65438+February 2.

It can be seen that only Tomb-Sweeping Day, which was originally in early March, was advanced to 3 1 in February, and the other 23 solar terms were in early and middle months.

New 24 solar terms songs

The spring rain shakes the spring and the valley days, and the summer is full of mountains and summers.

Autumn dew, autumn frost, little snow in winter and cold in winter.

There are two festivals every month, except the end of February.

The first half of the year is 1 month 16, and the second half is April 19.

This December balanced calendar is very simple: there is only one day difference between big and small months, which eliminates the most unreasonable shortcoming of the Gregorian calendar-February is too short. And the gap between the four seasons in the first half of the year is minimized and easy to remember. Taking beginning of spring as New Year's Day is based on astronomy and not limited to astronomy. The balance between months and seasons also brings great convenience to statistics.

Therefore, we can completely replace the current Gregorian calendar with a balanced December calendar!