Why are there so many constellations in the sky, but only 12 constellations?

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. By connecting these associations (rich imagination and creativity) in series, these constellations are visualized; 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".

In the whole celestial sphere, there are eighty-eight constellations in the celestial sphere, but in the ecliptic, there are not only twelve constellations, but strictly speaking, fourteen constellations.

Besides the familiar twelve constellations, the other two are Pisces and Ophiuchus. In fact, these two constellations only occupy a small part in the actual position of the ecliptic, unlike the other twelve constellations, almost all of them are included in the ecliptic. Ophiuchus is the only constellation that is crossed by the zodiac but does not belong to the zodiac. Due to the precession of the earth's axis, the vernal equinox moved from Aries to Pisces, so the time when the sun entered each constellation changed greatly.

1928, the International Astronomical Union officially announced the names of 88 constellations, which were divided into 3 celestial regions, 29 in the northern hemisphere, 47 in the southern hemisphere and near the ecliptic 12. Now the constellation we often say is "Zodiac 12 Palace". There are 12 constellations: Aries → Taurus → Gemini → Cancer → Leo → Virgo → Libra → Scorpio → Sagittarius → Capricorn → Aquarius → Pisces.