In recent decades, the Western signs of the Zodiac have become popular because of an increasingly widespread interest in astrology, the ancient belief in a connection between the movements and positions of the Sun, the Moon, the planets and the stars, and human events.
The 12 signs of the Zodiac are related to the belief that people born on certain dates of the year have in common specific personality traits – for example, people born between March 21st and April 20th tend to be proactive and perhaps impulsive or aggressive, and share other behavioural features as well.
Every year, the Sun moves around the celestial sphere, tracing a path along the ecliptic against the background of stars. When we look at the sky by day, we cannot see the stars or the planets because the light of the Sun doesn’t allow us to. By night, on the other hand, we can watch the stars, the planets and the Moon, although not the Sun.
However, astronomers know the Sun’s apparent position at each moment and know that in every 24-hour cycle its position relative to the background of stars changes a little – the equivalent of approximately one degree of the 360 degrees of the ecliptic.
On the other hand, astronomers also know that every year around March 21st the Sun is at a specific location of the celestial sphere, at a moment known as the Vernal or Spring Equinox. This location is basically the same every year, and it is equivalent to zero degrees of the Zodiac, that is, the zero degrees of Aries, the first sign of the Western Zodiac.
In the traditional Chinese solar calendar, something like this happens as well. However, instead of considering the March 21st Vernal Equinox to be the astrological starting point of the year, the Chinese consider February 4th the starting point. For them, the Spring Equinox is not the beginning of their cosmic spring but the season’s culminating moment.
Therefore, the beginning of the Chinese solar year occurs every year around February 4th, which corresponds to the beginning of the ‘month of the Tiger’ (the month of the Earthly Branch yín 寅), the first of the three months of the cosmic ‘spring’ season (chūntiān 春天).
Since both Western and Chinese Zodiacs and the 24 Chinese Solar Terms all refer to the ecliptic, it is possible to establish a correspondence between the beginnings of the months of both Zodiacs and the beginning of each Solar Term, as we show in the diagram included with this text.
NOTE The Chinese solar year is different to the Chinese lunar year, as it is based on the relative apparent position of the Sun while the lunar year is based on the relative position of the Moon. When the Sun and the Moon meet at the same ecliptic longitude, there is a New Moon, which always marks the beginning of a new lunar month.
Unlike the Chinese solar year’s beginning date, the date of the beginning of the Chinese lunar year changes yearly.
The first day of the first lunar month of the year marks the beginning of the Chinese lunar year, known as the Chinese New Year or the Chinese Spring Festival.
The first day of the lunar year is roughly the day of the New Moon closest to lìchūn 立春 (‘Beginning of Spring’, around February 4th).
In 2024, the Chinese Lunar New Year’s first day is February 10th.
This division of the ecliptic is not substantially different from the ancient division of the apparent movement of the Sun around the Earth through the year in Western tradition.
However, the Western Zodiac begins with the Spring Equinox (for the Northern Hemisphere) on approximately March 21st each year, which corresponds to the beginning of the zodiacal sign of Aries. The Chinese solar year, on the other hand, begins 45 days earlier with the beginning of the lichun 立春 solar term, around February 4th. That point, which corresponds to 315 degrees of the ecliptic, marks the beginning of the yin 寅 (Tiger) month of the Chinese solar year.
In other words, the beginning of the solar terms, the Chinese solar months, and the Western Zodiacal signs are interconnected because they are all based on the Sun’s apparent path against the background of stars.
