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An Overview Of Astrology

Illustrated ZodiacDefinition Of Astrology

Astrology is a system for interpreting the positions of celestial bodies, primarily the Sun, the Moon, and the planets, as they move through an area of the sky called the zodiac. Astrology is a model for describing all that exists on Earth, particularly human personality and experience.

Tropical Astrology

In the Western world, most astrologers use a type of astrology called tropical astrology, which is based on the Earth's four seasons. Each year, the first day of spring (the vernal equinox) marks the beginning of the tropical zodiac.

The Zodiac And The Signs

The 12 Zodiac Signs
Aries Libra
Taurus Scorpio
Gemini Sagittarius
Cancer Capricorn
Leo Aquarius
Virgo Pisces

The tropical zodiac is a great circle of area seen in the Earth's southern sky from the Earth's northern hemisphere. This zodiacal circle is divided into twelve equal sectors called signs.

Each sign is thirty degrees wide (length of longitude). The borderline between each sign is called a cusp.

Regarding human personality, each sign represents a unique way of being, point of view, or archetype. The function of each sign is to modify other celestial factors.


Although the astrological signs of the zodiac have the same names as some astronomical constellations, the signs and these constellations are not the same thing and their sky positions do not precisely line up.

Note, some astrologers use a type of astrology called sidereal astrology which does use constellations instead of signs. At Astromonica, we use tropical astrology (based on signs), not sidereal astrology (based on constellations).

The Planets And The Ecliptic

The 10 Planets

The signs of the zodiac are the backdrop over which the Sun, Moon, and planets move. These heavenly bodies move in a counterclockwise fashion through the zodiac.

Humans are familiar with the apparent daily motion of the Sun rising in the east and setting in the west, which is due to the Earth's daily rotation on its axis. The apparent path of the Sun is called the ecliptic. The Moon, the planets, and the signs also will rise and set each day, along the ecliptic.

While astrologers know that the Sun and the Earth's Moon are not planets as defined by astronomy, for convenience astrologers refer to the Sun and the Moon as planets. Planets represent fundamental life principles. These principles are found within all people and are experienced as urges and needs. For example, the Sun represents one's sense of individuality and the Moon represents subconscious predisposition.

The Houses

Similar to the signs, astrologers organize the sky (where the zodiac resides) into twelve areas called houses. Unlike the signs, the houses vary in length of longitude and do not rise and set each day; meaning houses retain their positions relative to the Earth's horizon.

Like the signs, the houses have cusps. However, while all sign cusps are precise borderlines, some house cusps function more like a varying range of peak activity.

For people, the houses represent specific areas of life, such as work and marriage. The planets and signs symbolically facilitate action within the houses.

The Aspects

Astrologers also consider specific geometric angles called aspects which are formed between various celestial factors, especially the planets. In terms of individuals, aspects link planets together to symbolize complex expressions of personality.

The Birth Chart

The most essential tool of astrology is a sky map called the birth chart or the natal chart. The birth chart uses a wheel to symbolize the zodiac. Represented within the wheel are the planets, signs, aspects, houses, and other celestial factors.

Complete birth charts are constructed using precise astronomical calculations based on accurate birth data: the date, the time, and the location. Birth charts can be constructed for a variety of things, such as a person, an event, or a nation.

The Horizon And The Rising Sign

An important feature of the birth chart is the horizontal line across the center of the chart. This line represents the Earth's horizon. Because the birth chart is a map of the sky (not land), the left side of the chart represents east, the right side represents west, the upper part represents south, and the lower part represents north.

The sign rising on the eastern horizon at the time of birth is called the rising sign. The precise degree of longitude of that same sign is called the Ascendant. For people, the Ascendant functions as an immediate, spontaneous, personal expression of distinct traits that may or may not harmonize with the rest of the personality.

The Sun Sign

Most people are familiar with the pop astrology question "What's your sign?" Unfortunately, this question creates some misunderstandings about authentic astrology.

Firstly, the questioner is improperly using the word "sign" to mean "Sun sign." After all, the questioner is really asking, "In what sign was the Sun located at the time of your birth?"

Secondly, the question "What's your sign?" implies that the Sun sign is the total application of astrology; that the Sun sign alone completely describes the personality of the individual. While the Sun sign is definitely an important factor in describing personality, it is not the only factor.

As stated here earlier, authentic astrology uses complete, accurate birth charts comprised of the Sun and many other factors. Astrologers then synthesize these factors in the individual birth chart into a unique personality profile.

Lastly, as in the term "Sun sign," the word "sign" can be applied to other factors in the birth chart too. For example, one can say "Moon sign" or "sign of the Ascendant."

The Primal Triad

When interpreting a birth chart for a person, astrologers usually focus first on the condition of the Sun, Moon, and Ascendant. Because of their major importance, they are collectively referred to as the primal triad.

Sometimes people refer to themselves as being a "double" or "triple" of a sign. For example, "I'm a double Aries" or "I'm a triple Leo." In the case of the "double," the person usually means his Moon sign or his Ascendant sign is the same sign as his Sun sign. In the case of the "triple," the person's Sun, Moon, and Ascendant (the primal triad) are all the same sign.

Born On The Cusp

When a person says he was "born on the cusp," he is saying he was born when the Sun was located near the beginning or the ending of a Sun sign. Such a person might wrongly assume that he has the Sun sign traits of both signs bordering the cusp in question. Contributing to the cusp confusion are the generalized birth dates listed for each Sun sign period in the popular horoscope columns.

An accurate birth chart will determine the correct sign position for the Sun (and for all the planets), thus revealing the traits of the one, true Sun sign.