Is the constellation based on the lunar calendar or the solar calendar?

The constellation looks at the solar calendar.

When everyone is born, every planet in the solar system, regardless of its size, including sun, moon, Venus, Jupiter, Mercury, Mars, Saturn, Neptune, Uranus and Pluto, runs at different angles and distances, so each planet and its corresponding 12 constellation are mutually causal.

The sun sign is the most frequently mentioned in astrology. As long as you know a person's date of birth, you can find out his sun sign. The twelve constellations begin in spring, that is, when the sun runs to the vernal equinox around March 20 every year, they will be sorted in order: Aries, Taurus, Gemini, Cancer, Leo, Virgo, Libra, Scorpio, Sagittarius, Capricorn, Aquarius and Pisces.

To sum up, everyone belongs to different constellations because of the different birth dates of the Gregorian calendar (that is, the Gregorian calendar).

Note: We should adopt a scientific attitude towards horoscope, believing rather than superstitious.