The Zodiac (Greek: ζῳδιακός, zōidiakos) is a circle of twelve 30° divisions of celestial longitude called signs. The division is centered upon the ecliptic, that is, the apparent path of the Sun across the celestial sphere over the course of the year. Although the zodiac is use in astronomy as the basis of the ecliptic coordinate system, it is today mostly associated with astrology.
Helena Petrovna Blavatsky defined it as follows:
Zodiac (Gr.). From the word zodion, a diminutive of zoon, animal. This word is used in a dual meaning; it may refer to the fixed and intellectual Zodiac, or to the movable and natural Zodiac. “In astronomy”, says Science, “it is an imaginary belt in the heavens 16° or 18° broad, through the middle of which passes the sun’s path (the ecliptic) .“It contains the twelve constellations which constitute the twelve signs of the Zodiac, and from which they are named. As the nature of the zodiacal light—that elongated, luminous, triangular figure which, lying almost in the ecliptic, with its base on the horizon and its apex at greater and smaller altitudes, is to be seen only during the morning and evening twilights—is entirely unknown to science, the origin and real significanće and occult meaning of the Zodiac were, and are still, a mystery, to all save the Initiates. The latter preserved their secrets well. Between the Chaldean star-gazer and the modern astrologer there lies to this day a wide gulf indeed; and they wander, in the words of Albumazar, “‘twixt the poles, and heavenly hinges, ‘mongst eccentricals, centres, concentricks, circles and epicycles”, with vain pretence to more than profane human skill. Yet, some of the astrologers, from Tycho Braire and Kepler of astrological memory, down to the modern Zadkiels and Raphaels, have contrived to make a wonderful science from such scanty occult materials as they have had in hand from Ptolemy downwards. (See “Astrology”.) To return to the astrological Zodiac proper, however, it is an imaginary circle passing round the earth in the plane of the equator, its first point being called Aries 0º. It is divided into twelve equal parts called “Signs of the Zodiac”, each containing 30º of space, and on it is measured the right ascension of celestial bodies. The movable or natural Zodiac is a succession of constellations forming a belt of in width, lying north and south of the plane of the ecliptic. The precession of the Equinoxes is caused by the “motion” of the sun through space, which makes the constellations appear to move forward against the order of the signs at the rate of 501/3 seconds per year. A simple calculation will show that at this rate the constellation Taurus (Heb. Aleph) was in the first sign of the Zodiac at the beginning of the Kali Yuga, and consequently the Equinoctial point fell therein. At this time, also, Leo was in the summer solstice, Scorpio in the autumnal Equinox, and Aquarius in the winter solstice ; and these facts form the astronomical key to half the religious mysteries of the world-—the Christian scheme included. The Zodiac was known in India and Egypt for incalculable ages, and the knowledge of the sages (magi) of these countries, with regard to the occult influence of the stars and heavenly bodies on our earth, was far greater than profane astronomy can ever hope to reach to. If, even now, when most of the secrets of the Asuramayas and the Zoroasters are lost, it is still amply shown that horoscopes and judiciary astrology are far from being based on fiction, and if such men as Kepler and even Sir Isaac Newton believed that stars and constellations influenced the destiny of our globe and its humanities, it requires no great stretch of faith to believe that men who were initiated into all the mysteries of nature, as well as into astronomy and astrology, knew precisely in what way nations and mankind, whole races as well as individuals, would be affected by the so-called “signs of the Zodiac”.
- Helena Petrovna Blavatsky, The Theosophical Glossary (Krotona, CA: Theosophical Publishing House, 1973), 387-388.
- Two Lost Keys: The Bhagavad-Gita - the Zodiac by W. Q. Judge