[Edit this paragraph] The definition of constellation
refers to a group of stars in the sky. In the three-dimensional universe, these stars have no actual relationship with each other, but their positions on the celestial sphere are similar. Since ancient times, people have been interested in the arrangement and shape of stars, and have naturally connected some stars with similar positions to form constellations.
Constellations play an important role in astronomy; astrology also borrows the images of the 12 constellations of the zodiac, but astronomers regard astrology as a pseudoscience that does not use real scientific methods.
Basically, forming stars into constellations is an arbitrary process, and different civilizations have different constellations composed of different stars - although some constellations composed of more conspicuous stars have different constellations. Roughly the same in civilizations, such as Orion and Scorpio.
The International Astronomical Union divides the sky into eighty-eight formal constellations with precise boundaries, so that every star in the sky belongs to a specific constellation. Most of these formal constellations are based on the traditional ancient Greek constellations handed down from the Middle Ages.
In order to make it easier to identify stars, people divide them into several areas according to the natural distribution of stars in the sky. Various sizes. Each area is called a constellation. Use lines to connect the bright stars in the same constellation to form various shapes. According to their shapes, they are named after similar animals, artifacts or mythological figures, such as Cygnus, Andromeda, etc. The stars in each constellation are arranged in lowercase Greek letters according to their brightness, such as Alpha Ursa Major, Beta Ursa Major, etc.
A constellation is the total of celestial space projected on an area on the celestial sphere. Therefore, it is inaccurate to say that a certain constellation is within/outside the Milky Way.
[Edit this paragraph] The origin of constellations
Constellations originated in ancient Babylon, one of the four ancient civilizations. The ancient Babylonians divided the sky into many areas, called "constellations" , but at that time the constellations were of little use and even fewer were discovered and named. The 12 constellations on the zodiac were originally used to measure time, not as they are now used to represent people's personalities. Around 1000 BC, 30 constellations were proposed. There, the Tigris and Euphrates rivers flow from northwest to southeast and flow into the Persian Gulf, so it is also called the "Two Rivers Basin" area.
After the Mesopotamian culture spread to ancient Greece, it promoted the cultural development of ancient Greece. Ancient Greek astronomers supplemented and developed the Babylonian constellations and compiled the ancient Greek constellation table. In the 2nd century AD, the ancient Greek astronomer Ptolemy compiled 48 constellations based on the astronomical achievements of the time. And use imaginary lines to connect the main bright stars in the constellation, imagine them as animals or characters, and give them appropriate names based on myths and stories. This is the origin of the name of the constellation. Most of the 48 constellations in Greek mythology live in the northern sky and north and south of the equator.
After the Middle Ages, the rise of capitalism in Europe required outward expansion, and navigation developed greatly. Ships sailing on the sea need navigation at any time, and the stars are the best guiding lights. Among the stars, constellations have special shapes and are the easiest to observe. Therefore, constellations have received widespread attention. When Magellan sailed around the world in the 16th century, he not only used constellations for navigation and orientation, but also studied the constellations.
In 1922, the International Astronomical Union General Assembly decided to divide the sky into 88 constellations, and their names were basically based on historical names. In 1928, the International Astronomical Union officially announced the names of 88 constellations. These 88 constellations are divided into three celestial regions, 29 in the northern hemisphere, 47 in the southern hemisphere, and 12 near the celestial equator and ecliptic.
There are nearly 6,000 stars visible to the naked eye, each of which can be classified into a unique constellation. Each constellation can be identified by the shape of its bright stars.
In order to facilitate research, people divide the starry sky into several areas, which are called constellations. China has long divided the sky into three walls and twenty-eight constellations. "Historical Records·Tianguan Shu" has quite detailed records. Sanyuan refers to the three areas around the North Celestial Pole, namely Ziweiyuan, Taiweiyuan and Tianshiyuan. The twenty-eight constellations are the 28 areas near the ecliptic and the white path, that is, the seven constellations in the east: Jiao, Kang, Di, Fang, Xin, Wei, and Ji. China’s achievements in stargazing were earlier than those in the West. The Chinese say that there are 28 constellations in Sanyuan. , dividing the constellations in the sky into three major 28 categories, instead of only the 12 Western constellations. The most important of them is Zi Weiyuan. Chinese stargazing is now collectively referred to as the Ziwei constellation, which is different from the twelve constellations in the West. There are fourteen main stars in the Ziwei constellation: Ziwei, Tianji, Sun, Wuqu, Tiantong, Lianzhen, Tianfu, Taiyin, Tanlang, Jumen, Tianxiang, Tianliang, Qisha, and Pojun . It can be divided into yin and yang according to the Book of Changes, which corresponds to four major categories of human personality: pioneering, leadership, supportive, and cooperative.