What is the basis for the division of the 24 solar terms?

According to the solar ecliptic, the traditional calendar in China divides the ecliptic into 24 arc segments, with each 16 as one breath and * * * as 24 qi. A whole year (tropic year) is divided into 24 periods. It's called the twenty-four solar terms. Starting from the longitude of the vernal equinox, every time the sun runs 15 on the ecliptic, it becomes a solar term. The time of each solar term is about half a month apart, and it is listed in twelve months respectively. The beginning of the month is called solar term, and the middle of the month is called gas. That is to say, the odd twelve gases, including beginning of spring, are called solar terms, and the even twelve gases are called middle gases. Since the slight cold, every 30-degree increase in the solar meridian is called the beginning of a solar term. * * * meter; There are twelve solar terms: slight cold, beginning of spring, fright, Qingming, long summer, awn seed, slight summer heat, beginning of autumn, Bailu, cold dew, beginning of winter and heavy snow. Starting from the solstice in winter, every 30-degree increase in the meridian of the sun is called the beginning of qi. * * * Count: winter solstice, severe cold, rain, vernal equinox, Grain Rain, Xiaoman, summer solstice, big trees, early trees, autumnal equinox, early frost and light snow. The start date of each solar term is similar every year in the solar calendar (only one day at most).

Working people in our country have compiled the 24 solar terms into catchy jingles during thousands of years of farming activities. The time characteristics of the 24 solar terms are easy to remember and master. This is a clever creation.

Spring rains shake spring and clear valleys,

Summer is full, summer is full, summer is full.

Autumn dew and autumn frost,

It snows in winter, it snows in winter, and it's a little cold in winter.

In the first half of the year, July 2 1 day,

Come in the second half.

Two festivals in a month remain unchanged,

Only one day at most.

The 24 solar terms are closely related to people's production and life besides being well remembered and mastered. In the long-term practice, the working people of our country have compiled 24 solar terms into songs to guide agricultural production practice and people's daily life. It is still in use until now, and it is not out of date. Although science and technology have developed to the present age, the 24 solar terms still have positive guiding significance for the weather.

Beginning of spring Yang turns, and the rain crosses the Yanhe River;

Frightened crows, the vernal equinox is exhausted;

Enigmatic busy planting wheat, Grain Rain busy farming;

The long summer goose feathers live, and the birds come to the whole;

Planting awns in May, without cotton in summer solstice;

It is not hot in the summer, but hot in the dog days;

Beginning of autumn is busy playing indigo, and busy sharpening knives and sickles in summer;

In the Millennium, there is no land in the autumn equinox;

The frost has changed before the cold dew is cold;

In the early winter of October, light snow wants to seal;

The snowy river is frozen, and the ship can't be transported on the solstice in winter;

The slight cold is not too cold, and the great cold lasts for three or nine days; Middle and lower reaches of the Yellow River.