How is the age of the twelve constellations calculated?

People divide the sky into regions and become sky regions. According to the shapes of stars in different regions and people's imagination, they have the concept of constellation. There are 12 constellations on the ecliptic plane (the * * * orbital plane of the earth, on which the sun seems to revolve around the earth), that is, the Zodiac Palace 12. On the earth, the sun goes around the earth once a year, passing through a zodiac in about 15 days, and setting down in turn from the vernal equinox.