Interpreting a horoscope involves consideration of planetary positions, house
cusps and the angles made by the planets to both (aspects). The signs of the zodiac provide
the framework in which the planets interact. Indeed, the one thing almost everyone knows about astrology is their "sun
sign," "birth sign" or "star sign," which actually details the apparent location of the sun at the
time they were born.
As the earth orbits the sun during the year, the sun appears from earth to move along a line relative to the fixed stars.
This line is called the ecliptic, and the band that extends to about eight degrees either side of this line is the zodiac.
Because the planets orbit the sun in approximately the same plane, they too appear to move through the zodiac over time.
Ancient astrologers divided the zodiac into twelve equal parts and named each after a constellation in that area of the sky.
These are, of course, the twelve signs of the zodiac:
If someone is an Aquarius, say, it simply means that the sun was in the sign of Aquarius at the time they were born. The
sun is in Aquarius from around January 20th to February 18th each year, so anyone born between these dates is an Aquarius.
Note that, because of factors like leap years and time zones, the sun may enter or leave a sign earlier or later than the
usual dates, so anyone born on the cusp (i.e. near one of the end dates between two signs) should check with an astrologer
to discover their sun sign. An accurate time and location of birth may be necessary to assess this correctly. For example,
someone born at the start of Aquarius may actually be a Capricorn, or at the end a Pisces. Click on any of the signs above
to find out what astrology says about individuals born with the sun in that sign.
The Precession of the Equinoxes
The equinoxes are those two days of the year when day and night are of equal length (around March 21st for the
vernal equinox and September 21st for the
autumnal equinox). The sun enters Aries around March 21st, the time
of the vernal equinox, but what is actually meant by this? It simply means that the sun enters that area of the zodiac that is
governed by the sign of Aries.
When the signs of the zodiac were first named, over 2000 years ago, the part of the zodiac the sun reached at the vernal
equinox did indeed contain the actual constellation of Aries. The earth slowly wobbles as it turns (each wobble taking about
26000 years to complete), and this causes a phenomenon known as the precession of the equinoxes. Basically, this means that
the apparent position of the sun in the zodiac at the equinoxes gradually shifts backwards as time moves on. By now the sun
has regressed one whole constellation, so at the vernal equinox the sun can now be seen in the
constellation of Pisces.
Critics often cite this apparent discrepancy as a reason why astrology cannot be valid, but this is to misunderstand the
distinction between the signs and the constellations of the zodiac. The signs divide the zodiac and the year into fixed
compartments of influence; the constellations were merely used in the original naming of the signs. So someone born on
March 25th is definitely an Aries, as they were born when the sun was in a location corresponding to the
sign of Aries, even though nowadays the sun would appear physically in the
constellation of Pisces, and in future the constellation of Aquarius, and so on. A much more
damning criticism of the legitimacy of astrology is the lack of agreement between the various house
As an aside, there is a branch of astrology, sidereal astrology, that attempts to use the physical zodiac of constellations
to position planets; but it is much more common and cogent to use the zodiac of the signs, and this is called tropical astrology.
Qualities and Elements
There are common features and attributes shared among the signs, allowing them to be grouped together in a variety of ways.
The most common of these are the quadruplicities or qualities and the triplicities or elements, and these are explained in
Qualities and Elements.