How are constellations formed?

People in ancient times had to know the changes of seasons in detail for animal husbandry and farming. They noticed that the stars in the sky have different arrangements in different seasons. In order to memorize and spread this knowledge, they use their imagination to connect the chaotic stars in the sky, which is the origin of the constellation.

In order to know the stars and study celestial bodies, ancient people artificially divided the starry sky into several regions long ago. China called it the Star Officer and the West called it the Constellation. In ancient China, the sky was divided into three walls and twenty-eight lodgings, and the earliest complete written record can be found in Historical Records Tianguanshu.

Sanyuanzhe, three areas near the North Celestial Pole: Ziweiyuan, Taiweiyuan and Tianshiyuan. The division of walls is not strict and clear. Wei Zibi generally includes Ursa minor, Draco, Panthera, Cepheus, Cassiopeia, Ursa major, Aries, Canis, Auriga and so on. Taiwei Courtyard is equivalent to the following constellations: Leo, Backrow, Virgo, Canis Major, Ursa Major and Little Lion. Tianshiyuan is relatively closer to the Milky Way in summer and autumn, including Ophiuchus, Hydra, Shield, Eagle, Five Immortals and Northern Corona.

Twenty-eight hostels are divided into four star areas, called four elephants, named after animals:

Oriental Black Dragon: Seven nights, namely Jiao, Kang, Bian, Fang, Xin, Wei and Ji.

Xuanwu in the north: seven nights for the battle, cattle, women, empty, dangerous, houses, walls.

Western White Tigers: Kui, Lou, Wei, Chang, Bi, Gou, Shen, etc.

Southern Suzaku: seven nights of well, ghost, willow, star, Zhang, wing and bird.

28 boarding houses are widely distributed among the people in China. Astronomers in the Han Dynasty once described it like this: "The black dragon curled up on the left, the white tiger squatted on the right, the suzaku flew forward, and the turtle circle was in front." In fact, it describes the astronomical phenomena shortly after dusk in early spring in the Central Plains of China.

The largest of the 28 lodging houses is Shu Jing, with a right ascension span of about 33 degrees, while the smallest lodging and ghost lodging are only 2-4 degrees.

China's star naming system was formed around 270 AD. During the Three Kingdoms period, a surname of Wu asked Chen Zhuo to compile a catalogue with 283 stars, *** 1464. Many of them were named after the official names of feudal emperors and generals.

The origin of western constellations can be traced back to Babylonians about 3000 years ago. By the second century A.D., astronomers in ancient Greece had generally determined the constellation of the northern sky area, while the constellation of the southern sky area was determined after the successful voyage around the world in the seventeenth century.

1603, according to the suggestion of German astronomer J. Bayer, the naming of stars was divided into constellations, that is, according to the brightness order in each constellation, they were represented by Greek letters. But there are only 24 Greek letters, and there are generally more than 24 stars in the constellation. For example, there are as many stars as 125 in Ursa Major. In order to solve this contradiction, frans Tide of Britain published a catalogue in 17 12, and the stars in the catalogue are numbered according to the right ascension in the constellation. So at present, except for the 24 bright stars in the constellation, they are all named after the number in the catalog plus the constellation name, such as Cygnus 6 1. Obviously, this number has nothing to do with the brightness order.

In order to unify the division of constellations, the International Astronomical Union announced the names and ranges of 88 constellations in the whole day at 1928 after research and discussion, and stipulated that the boundaries of constellations should be divided by right ascension and right ascension. The sizes of constellations vary greatly. For example, the largest constellation Ursa major covers an area of 1300 square degrees, while the smallest constellation Southern Cross is only 68 square degrees (the whole day area is 465,438+). The number of stars visible to the naked eye in each constellation is more or less and not equal.