Constellation is just a frame _ Constellation is just a frame?

Generally speaking, the framework of China constellation is a system of "three walls and twenty-eight lodges". We know that the earth revolves around the sun once a year, so it seems to us on earth that the sun moves slowly on the starry background once a year and returns to its original position (of course, we can't see the stars when the sun is high in the sky, but we can infer this by observing the stars around it after sunset or before sunrise). The route we see the sun moving slowly is called the ecliptic. Moreover, the ancients have long discovered that the route taken by the moon and the five planets of gold, wood, water, fire and earth is also near the ecliptic. Because we want to measure the position changes of these moving celestial bodies, the starry sky near the ecliptic is particularly important. So the ancients divided this part of the starry sky into 28 parts along the ecliptic, and each part was called a "night". Together, these 28 constellations are called "28 nights".

Why is it divided into 28 parts? Because the moon also roughly runs in this "belt", but the speed of the moon is much faster than that of the sun, and it takes more than 27 days for the moon to make a circle on the background of stars, so the ancients got a neat number: 28, so that the moon makes a circle a day. 28 can be divisible by 4, so that when the sun goes, it can be divided into four parts, and each part is a season. Listen, the ancients were very thoughtful. Then why is it called "Sue"? "Stay" means "stay" and "stay". The ancients imagined that since these constellations were intended to record the journey of the moon, all the chariots and horses on the earth would travel during the day and stay at night, and it would be better for the moon to do the same, so these constellations were called "small houses" and each "small house" was a "moon station". When twenty-eight hostels are divided into four parts, they are collectively called "four elephants" and have an animal name. They are:

Oriental black dragon: horn, sound, correlation, room, heart, tail, dustpan;

North Xuanwu: bucket, cow, female, empty, dangerous, house, wall;

Western White Tigers: Kui, Lou, Stomach, Zan, Bi, Gou and Shen;

Southern Suzaku: Well, ghosts, willows, stars, Zhang, wings, birds.

Pale means green, and black dragon means "Qinglong"; Suzaku, according to scholars' research, is a quail; Only Xuanwu is the most special, it is a two-in-one animal image-snake turtle. In addition, it is strange that, somehow, these 28 huts are not evenly distributed, but have different widths. According to the ancient 365 and 1/4 degrees, the widest well is over 30 degrees, and the narrowest is only one or two degrees. "Sanyuan" is the other three constellations. Round the ecliptic on the 28th night, splitting the celestial sphere in two. People in China spend more time watching the northern part of the celestial sphere, so this part is more important to us. Therefore, our ancestors built "three walls" on the inner surface of this hemisphere surrounded by 28 nights. "Wall" refers to walls, and each wall has two walls, which form an almost circular Xiaotian area. The "three walls" are only distributed in a three-point shape, just like the positions of the three vertices of a regular triangle. The extreme center in the north is Ziwei Garden, and the other two are Taiwei Garden and Tianshi Garden.

As mentioned earlier, the traditional constellation in China is not called a constellation, but a "star official". It turns out that the ancients moved the emperors' palaces, court officials and so on to the sky. Ziweiyuan is the imperial palace in the sky. The Emperor of Heaven sits in the central North Pole, surrounded by empresses, princes and eunuchs. Surrounded by the Prime Minister (Cheng), senior cabinet leaders (Shu, Fu and Bi) and court guards. Will be introduced in detail later.

The Imperial Courtyard is a symbol of the imperial administration, where emperors and ministers handle government affairs. Its center is the emperor's throne, next to the prince, lieutenants and minions, surrounded by near ministers, three fair ministers, nine ministers and the prince. There is a prime minister (on camera), who is in a prominent position of "one person is below and ten thousand people are above". For all government officials, his words are only one level worse than the imperial edict; Deputy Prime Minister (second minister), Minister of National Defense (general), Minister of Public Security Supervision (right law enforcement), President of the Supreme Court (left law enforcement), and various officials; There are also security guards, such as Lang Jiang, Langwei and Hu Ben. Not far from Taiwei Courtyard, there is a constellation "Shao Wei". Why is it called "Shao Wei"? It turns out that its members are hermits, and this constellation is equivalent to a "shadow cabinet".

The sky and the city walls are more interesting. Guo Moruo has a poem called "The Market in the Sky", which reads:

"I think there must be a beautiful market in the ethereal sky, and some items displayed in the market must be rare in the world."

In fact, Tianshiyuan is really such a huge market in the sky, and it is a comprehensive trade market in which all the people in the country participate. Maybe it's because fair trade concerns people's lives. The area of Shi Tian Garden is much larger than that of Taiwei Garden. Since it is a national market, it must be carried out under the leadership and intervention of the government, so the emperor of heaven led the princes to sit in the town. Among them, there is the "Emperor" star, where princes form a wall, a central government official (nine planets in Tian Mi) directly directs it, a market management center (tower), and then shops and stalls-car shops, pillar shops and meat shops, that is, shops or workshops. A store refers to a car carrying department stores selling along the street; List all kinds of shops, it is estimated that department stores, daily necessities, small commodities, jewelry; Slaughterhouse includes places for banquets, entertainment and accommodation. The market has also set up a number of measurement supervision departments, such as silk, bucket, welcome and other constellations.

What do you mean by "the southern and northern sections of the zodiac"? As we all know, there is an included angle of 23.5 degrees between the ecliptic and the equator. In this way, the northernmost section of the ecliptic on the equator of the celestial sphere is called the "northern section of the ecliptic", and vice versa.

The black dragon in the east, the basalt in the north, the white tiger in the west and the suzaku in the south do not completely correspond to the starry sky in spring, summer, autumn and winter today. This may be related to the season and time when the ancients named them.

About in ancient times, on an early spring evening, stargazers stood in the wilderness and saw the twinkling constellations in the east flying in the air like a dragon, so they were called "Oriental Black Dragon". Looking up at the constellation hanging high in the southern sky, it seems that there is a red bird soaring in the sky, so it is called "Southern Suzaku"; Seven nights in the west, like the roar of tigers, is about to melt into the west, named "western white tiger"; At this time, the tortoise and snake in Xuanwu for seven nights have disappeared-it is disappearing under the horizon of the northern sky, so it is called "Northern Xuanwu". Zhang Heng, an astronomer in the Eastern Han Dynasty, once described it like this: "The black dragon curled up on the left, the white tiger slammed away from the right, the rosefinch fluttered in front, and the turtle circled behind." We only need to know that "four elephants" and "four seasons" are related, and we can't simply judge the four seasons by the order of the four elephants. At this point, it is necessary for us to add a little knowledge of spherical astronomy, which may be useful in many stories later. The earth we live in is constantly spinning. Because of its rotation, we geographically determined the poles and equator of the earth. We assume that the sky is also a sphere, called "celestial sphere". The two poles of the earth extend into the sky, namely, the "celestial North Pole" and the "celestial South Pole". The equator of the earth extends outward to the celestial sphere, and its intersection line is called "celestial equator". Because of the earth's rotation, we see the sun, moon and stars rise and set in the west for about 24 hours every day, which is called the "Sunday apparent motion" of celestial bodies.

As we mentioned earlier, because the earth revolves around the sun, it looks as if the sun is moving slowly in the starry sky on the earth. This is the so-called "annual apparent movement" of the sun. We can't directly see the position of the sun in the starry sky, but we always take the setting sun as the standard of "night". We can infer the position of the sun in the starry sky from the starry sky after sunset. At the same time, this part of the starry sky we see at night changes with the seasons, so it is called "Spring Night Starry Sky", "Summer Night Starry Sky", "Autumn Night Starry Sky" and "Winter Night Starry Sky" respectively.

Another thing to remember is that the position of the north pole of the celestial sphere is not fixed. It moved slowly in the sky, drawing a great circle with a radius of 23.5 degrees in 25800. This is caused by the sun and moon attracting the protruding part of the equator of the earth, which is called "precession". So different eras have different Polaris.