Precession and the Zodiac

I’m a Capricorn......Right? The Precession of the Equinoxes and the individual’s Horoscope.

By Caroline Tully.

The phenomenon termed “Precession of the Equinoxes” concerns the shift over the years which has resulted in the Zodiac signs no longer occupying precisely the position in relation to the Earth that they occupied several thousand years ago. Precession occurs because of the wobble of the Earth’s axis caused by the combined gravitational pull of the Moon and Sun which causes movement of the Earth akin to that of a gyroscope, forming a complete circle over 25,000 years. Because of this precession the 30-degree divisions called the Zodiac Signs do not now coincide with the actual constellations which they represent. Today the astronomical point known as “the first point of Aries” or 0 degrees Aries, is actually to be found around 7 degrees of the previous sign of Pisces. This makes a difference of 23 degrees. This supposedly does not affect Western Astrological theory as Western Astrologers use the constellation’s names to denote 30 degree areas of the ecliptic, the Sun’s apparent path around the Earth, rather than the constellations themselves. Western Astrologers argue that the system is not devalued by this phenomenon, however, as I will demonstrate, Precession of the Equinoxes can make a big difference to an individual’s Sun sign and Natal horoscope.

There is a fundamental difference between the Zodiac used in Hindu Astrology and the one used in the Western system. The Zodiac is an imaginary sphere of 360 degrees encircling the heavens inside of which the Sun, Moon and planets travel in their orbits. This circular space is divided into twelve equal parts of 30 degrees each, known as the Zodiac Signs. At one time, these signs corresponded to actual fixed star constellations, however, due to the Precession of the Equinox, which moves at a an average rate of 50-and-a-quarter seconds per year, or 1 degree every seventy-two years, the same connection between the Zodiac Signs and the constellations no longer exists. Because this difference adds up to around 23 degrees, when a Westerner refers to the Sun being in 15 degrees of Libra for instance, the statement is technically inaccurate, because the Sun, after being backed up by 23 degrees, would actually reside in Virgo.

The system that Western Astrologers use which is unrelated to the constellations is called the Tropical Zodiac. The older and more traditional Zodiac employed by the Hindus, where there is no difference between a star constellation and the sign name given to it is called the Sidereal Zodiac. To find the Sidereal position of a planet when looking in a Tropical (Western) ephemeris, 23 degrees will have to be subtracted from the planet’s position in a sign to give the actual, Sidereal location. Obviously our Western Horoscopes as we know them are “out” by 23 degrees which therefore changes the degree of every planet in the Horoscope and may move some planets into a different sign.

I will use my own Natal chart as an example. My Sun, in the Tropical system, is at 24degrees Capricorn. In the Sidereal system, 23 degrees are subtracted from my Sun’s position and the result is 1 degree Capricorn. My Sun is still in Capricorn, but if I had been say, 15 degrees Capricorn instead of 24 degrees, and subtracted 23 degrees to get a Sidereal position, my Sun would have become 22 degrees Sagittarius! This changes everything. My Sun would have actually moved into a completely different sign, and so anyone with a planet degree of less than 23 degrees in a sign will find that planet in a different sign when the Sidereal system is applied to their Horoscopes. This is most noticeable with the Sun sign as it is the sign most people identify with when we talk about “our horoscope”. I won’t have an Astrological “identity crisis” when I apply the Sidereal Zodiac to my Sun’s position because it is still in Capricorn – barely – but when I apply the Sidereal Zodiac to my Moon’s position I get a bit of a surprise.

In the Tropical position, my Moon is situated at 15 degrees of Scorpio. I fancy this position as I like to flatter myself with the Scorpionic traits such as an interest in the Occult, a relentless searcher into hidden realms and a deep, complicated type of person. After subtracting the 23 degrees from my Tropical Moon’s position however, I am alarmed to discover that my spooky, Scorpionic Moon has become a nice, helpful 22 degrees of fashion-designing Libra! My Ascendant, the sign on the horizon at the time of birth, in the Tropical Zodiac is at 25 degrees of Virgo, after adjusting to the Sidereal Zodiac, I am still in Virgo but only by 2 degrees. Everything else in my Horoscope progresses backwards into the previous sign. So the ACTUAL positions of the planets in your Sidereal Horoscope are NOT the same as those that you might find on your familiar Natal chart: they have all moved backwards by 23degrees.

The first scientific description of the cycle of Precession is credited to Hipparchus (2nd century BCE). As well as changing one’s Horoscope, Precession of the Equinoxes is also what determines what is known as the Astrological “Great Year”. It is generally agreed by Astrologers that it takes around 25,000 years for the wobbling axis of the Earth to make one revolution causing a “Great Year”, thus a different Zodiac sign is said to rule each period of around 2000 years within that “Great Year” of 25,000 years. These 2000 year periods are called “Great Months”. In recent decades, the concept of Precession has taken root in the popular imagination of the New Age with the supposed dawning of the Age of Aquarius. However, the assumption that we are at the dawning of this Great Age owes very little to the observation of the sky. Since about 100 BCE, the Equinox point has slowly been making its way through the constellation of Pisces and is only now beginning its progress through the second fish of the Pisces pair. It will not reach the same degree of longitude as the star Beta Piscium at the head of the fish until around CE 2813. The point of the Vernal Equinox is currently at Iota Piscis, which is around the center of the second fish in the Pisces constellation.

For readers who would like to obtain their own Sidereal Horoscope to compare with their Tropical, Western chart, I suggest that if you know your planet’s positions, just subtract 23 degrees from each position, which will often cause a planet to regress into its previous sign, or buy an Ephemeris which is a book with the Tropical positions of the planets in the signs and then subtract the 23 degrees, or find an Astrologer who calculates Sidereal charts. Some Western Astrologers have adopted the Sidereal Zodiac method, however it is usually thought of as an esoteric practice in a Western context.