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Zodiac

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Astrology->Common Elements->Zodiac->Signs (you can edit this template)

The zodiac is an imaginary band around the celestial sphere traced by the path of the Sun (or Moon) through the sky. The star constellations that straddle the path of the luminary make up the signs of the zodiac, and are each thought to represent a distinct astrological character. To ancient humans, the path of the Moon through the stars was easier to observe than the Sun and therefore the zodiac was composed of lunar mansions instead of sun signs. But the Moon is erratic in its movement and touches a lot of constellations (in fact there are as many as seventeen lunar mansions).

Eventually, astrologers began using the path of the Sun through the ecliptic and just twelve of the constellations as the foundation for the common zodiac. Although the Sun actually cuts through exactly thirteen constellations in its path across the sky, the constellation Ophiuchus is generally not included in the zodiac. Because the ecliptic lies in the general plane of the solar system, the Sun, Moon, and planets seem to move through the zodiacal constellations. The width of the zodiac allows for the fact that the orbits of the other bodies are inclined relative to plane of the ecliptic, and thus extend about 8º beyond it.

The Sun spends approximately the same amount of time in each of these constellations. Therefore the common western zodiac is split into twelve equal 30° segments, each of which is named after the constellation of stars originally discovered in that segment of the sky. At the time when the constellations were first assigned to the zodiac each constellation had already acquired generations of lore and observation associated with it by numerous cultures. Therefore these segments of the zodiac also took on rich symbolism and characterization and are now called astrological signs.

1 History
2 Precession of the Equinoxes
3 Traditions
- 3.1 Tropical Zodiac
- 3.2 Sidereal Zodiac
4 Zodiacal Constellations
5 References

History

The concept of the zodiac was originated by the Babylonians before 2000 BC as a method of visualizing the passage of time. The zodiac worked as a symbolic calendar. It was divided into twelve parts as suggested by the appearance of 12 moons in a year. The signs are geometric divisions of the celestial sphere, each corresponding to one twelfth of a year.

The signs of the zodiac, as enumerated by Egyptian astronomer Ptolemy in the 2nd-century AD, are the ones we know today. The same names are used for both signs in astrology and for constellations in astronomy, but it's important to make a distinction between signs and constellations. Signs are geometric sections, each 30° wide, corresponding with particular periods of time of the year, but which don't necessarily physically correspond with the constellations of the same name.

By the time of Ptolemy the zodiac was already at least two thousand years old. But together with its burgeoning astrological use the basic function and structure of the "calendar of the zodiac" remained. The sign of Aries marks the beginning of the year at the vernal equinox. The retreating crab in Cancer represents the retreat of the Sun from its farthest northern point at the time of the summer solstice. Leo, the symbol of fire, represents summer heat. The scales of Libra signify the balance between day and night at the autumnal equinox. The decline of the sun's power is represented in Scorpio by the scorpion, the symbol of darkness. The water-bearer, Aquarius, represents the rainy season which, in Egypt, meant the yearly flooding of the Nile. The fishes of Pisces, symbolize the return of life and the resumption of agriculture.

The concept of the zodiac spread form Babylonia to Greece and, from there, to Egypt where the Egyptians substituted their own symbolism. Aries became the Fleece. Two Sprouting Plants replaced the twins of Gemini. Cancer was re-named Scarabaeus. Leo became the Knife and Libra the Mountain of the Sun. Sagittarius was reduced to just an arrow. Capricorn became the image of life, represented by a mirror. Scorpio became a serpent. Aquarius became simply water, while Taurus, Virgo and Pisces were not changed.

Precession of the Equinoxes

Because they were originally modeled on their associated star clusters, non-astrologers often assume that the astrological signs actually are the constellations. However, there is no real correlation in geocentric astrology except through symbolism. The zodiac is a tool which measures cyclical time with respect to the Sun and Earth and contains associated symbolism to aid in divination, understanding and memory retention. The stars, on the other hand, are the table against which this measurement takes place. Nevertheless, the idea that the zodiac signs are somehow influenced by the constellations persists, and is rooted in the ancient idea of the stars representing gods. As a result, it disturbs some people to discover that the original twelve constellations have "shifted" over the last few thousand years relative to the zodiac, so that they no longer fall in the same segments of the zodiacal belt. Actually, it is not the stars that have shifted at all, but rather the equinox points upon which the tropical zodiac is based.

The equinox point moves backward through the constellations of the zodiac at the rate of about 50 arc seconds annually. The reason for this is complicated and has to do with the orbit of the Sun and the wobbling rotation of the earth. The equinox stays in each zodiac sign for approximately 2160 years. When the Babylonians were first playing around with splitting up the sky into zodiac belts, the vernal equinox actually did appear in the constellation of Aries (such that 0° of the zodiac sign of Aries would correspond to the beginning of the actual constellation of stars by the name of Aries). Today, however, the vernal equinox appears in the constellation of Pisces even though it is still measured in the tropical zodiac as 0° Aries.

Traditions

Tropical Zodiac

Western astrology primarily uses the tropical zodiac, which is based upon tropical time, or the apparent motion of the sun across the sky over the course of a year. The tropical zodiac fixes the position of the sun in the heavens at the northern hemisphere vernal equinox as the first point of the sign of Aries. However, because of the precession of the equinoxes this means the division into signs will be different than the placement of the actual constellations. For example, although the Sun always enters the astrological sign of Aries at the vernal equinox about March 20, it will not cross into the astronomical constellation of the same name until nearly a month later. The tropical zodiac therefore uses a view of the heavens as seen from Earth approximately 2600 years ago when the northern hemisphere vernal equinox did actually occur within the constellation of Aries.

This is not odd if one sees the zodiac as time measured relative to the earth and sun rather than relative to the stars. It is unfortunate that the signs are named after the constellations, because it creates an appearance of being out of sync. However, the signs accurately represent the time cycles they are meant to represent, and making adjustments to "catch up" with the actual placement of the constellations would render meaningless the wealth of observation and experience already achieved using this system. Therefore, if one has already invested time and effort into using this system, there is no reason to change. It is still very accurate using the existing body of knowledge concerning interpretation of horoscopes and the symbolism attached to the standard zodiac.

Sidereal Zodiac

Eastern astrology (e.g. Vedic or Jyotish) primarily uses the sidereal zodiac in which the signs are more aligned to their correct stellar constellations. However, the alignment still isn't exact, because the constellations all take up varying amounts of space along the ecliptic, whereas the signs each take up exactly 30°.

Those who favor the sidereal zodiac take into account the precession of the equinoxes. Because of a "wobble" in the earth's axis of rotation over a period of about 26,000 years the point at which the vernal equinox advances in the sky by about 50.25 seconds of arc every year, or 1° 23' 45" per century. Advocates of the sidereal zodiac believe that the position of the signs should be fixed relative to the constellations.

If one decides to "switch" from tropical to sidereal zodiacs, it will be necessary to adjust more than the chart calculations. Zodiacs are tools to symbolically represent human experience over time. The system of measurement must be continuous, since time is continuous. Therefore, to interpret a chart in the sidereal zodiac, it is best to use the observations and teachings of those who have practiced using the sidereal zodiac over several generations. Even though the signs have the same names as the tropical zodiac, they may have slightly different meanings under that context. And the use of degree interpretation (as with dwads) becomes helpful in distinguishing the variations in expression.

Zodiacal Constellations

A traditional mnemonic to remember the signs:

The Ram, the Bull, the Heavenly Twins,

And next' the Crab, the Lion shines,

The Virgin and the Scales.

The Scorpion, Archer, and the Goat,

The Man who holds the Watering Pot,

And the Fish with glittering scales.

Sign	Symbol	Birthdates		Actual Astronomical Dates (as of AD 2000)
Sign	Symbol	Tropical	Sidereal	Actual Astronomical Dates (as of AD 2000)
Aries	ram	March 21 - April 19	April 14 - May 14	April 19 - May 13
Taurus	bull	April 20 - May 20	May 15 - June 14	May 14 - June 19
Gemini	twins	May 21 - June 20	June 15 - July 16	June 20 - July 20
Cancer	crab	June 21 - July 22	July 17 - Aug. 16	July 21 - Aug. 9
Leo	lion	July 23 - Aug. 23	Aug. 17 - Sept. 16	Aug. 10 - Sept. 15
Virgo	virgin	Aug. 23 - Sept. 22	Sept. 17 - Oct. 17	Sept. 16 - Oct. 30
Libra	scale	Sept. 23 - Oct. 22	Oct. 18 - Nov. 16	Oct. 31 - Nov. 22
Scorpio	scorpion	Oct. 23 - Nov. 21	Nov. 17 - Dec. 15	Nov. 23 - Nov. 29
Ophiuchus				Nov. 30 - Dec. 17
Sagittarius	archer	Nov. 22 - Dec. 21	Dec. 16 - Jan. 14	Dec. 18 - Jan. 18
Capricornus	goat	Dec. 22 - Jan. 19	Jan. 15 - Feb. 12	Jan. 19 - Feb. 15
Aquarius	water	Jan. 20 - Feb. 18	Feb. 13 - March 14	Feb. 16 - March 11
Pisces	fish	Feb. 19 - March 20	March 15 - April 13	March 12 - April 18