There are many constellations in the sky, so why are there only twelve constellations a year?

In ancient times, in order to facilitate navigation and observe astronomical phenomena, people connected the scattered stars in the sky through imagination. Half of them were named in ancient times, and the naming method was based on the myths and forms of ancient civilizations (including the myths and epics of Mesopotamia, Babylon, Egypt and Greece). The other half (mostly in the night sky in the southern hemisphere) was named only in modern times, and is often named after navigation instruments.

In ancient times, because of different regions, the way to see the starry sky was different! Now the world divides the sky into 88 regions and 88 constellations according to the constellation map.

The "constellation" we usually say refers to the "sun constellation"; That is, people on the earth are the center, and at the same time we can see which constellation the sun is in orbit (Greek zodiac: the circle made by animals, also known as the "zodiac"), so we can say what constellation that person is.

More than 2000 years ago, the Greek astronomer Hipparchus (190 ~ 120 BC) divided the ecliptic into twelve segments, with spring divided into zero, and every 30 degrees from the vernal equinox (that is, the zero degree of the ecliptic) as a palace, taking the main constellations contained in each palace at that time. Babies born when the earth moves to every bisector (constellation) will always have some similar characteristics when they grow up, including behavioral characteristics and personality characteristics. Connect these associations (rich imagination and creativity) in series to make the humanity of these constellations concrete; It also adds the color of myth and becomes an important part of culture (mainly Greek and Roman mythology).

This set of numerology has been developed and circulated for at least five thousand years, represented by these twelve constellations respectively. But these constellations do not represent a certain "star", but can only be regarded as "representative symbols of the same name".