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Deborah Houlding

Deborah Houlding





































Also by Deborah Houlding


The Moon - Lantern of Heaven

Venus - the two-faced goddess
Mars - solar hero or deadly villian?

Heavenly Imprints

Heavenly Imprints

Development of the Zodiac
and the early origins of
Aries & Taurus



by Deborah Houlding



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Precession


Being a circle, the zodiac has no obvious beginning, so a specific point must be determined from which measurement can commence. This is where the problems begin to occur, in particular because astrologers sought to align the zodiac with the four cardinal points that mark the alteration of seasons: the equinoxes (where the Sun crosses the equator in spring and autumn) and the solstices (where it is furthest from the equator in summer and winter). In the early Classical period these were regarded as fixed in space although, in fact, they are subject to an almost imperceptible precession at the rate of 50 seconds per year. What this means in simple terms, is that the Sun does not cross the equator at exactly the same place on the ecliptic each year. It crosses at a point 50 seconds of arc to the east of the previous year. During a lifetime this shifting point of intersection between the ecliptic and equator is so small as to be negligible, but over several centuries it will be noticed that the backdrop of stars that once lay behind the crossing point is moving westwards. This is the phenomenon of precession, caused by the Earth's axis slowly rotating around the celestial poles. Whilst the background of the fixed stars remain more or less constant to each other, the ecliptic's intersection with the equator slides backwards through the zodiac, completing one circuit in approximately 26,000 years - the 'Great Astrological Age'. The movement of the Vernal Equinox from one zodiacal sign to the next - by which we are presently moving from the Age of Pisces to Aquarius - is a subdivision of this cycle that takes approximately 2,160 years.

The need to correctly identify the position of the Vernal Equinox, which sees the crossing of the Sun from the southern hemisphere to the north around 21 March, was a matter of vast significance to ancient civilizations. The Sun's return to the equinox gave the official signal for the start of spring, a time of great jubilation and spiritual worship, where whole communities engaged in New Year festivities and ceremonies that spanned several days, dedicated to celebrating the return of the Sun's domination over the darkness of winter, the return of life over death. There can be no doubt that the ascent of the Sun to the Vernal Equinox had absorbed the interest of astrologers for thousands of years before the introduction of the equally-spaced, manufactured zodiac. When this new mathematical device was introduced, it was natural for astrologers to seek to place its starting point - philosophically at least - in alignment with the Vernal Equinox.

We should remember, however, that this problem did not apply to the ancient cultures - the great civilizations of the Egyptians and Mesopotamians, who placed such tremendous importance on precisely locating and dating the "return of the Sun." The astrologers of the ancient period were observers, driven by religious and social needs to correctly locate the Vernal Equinox in order to set their calendars and regulate society. The people of ancient Egypt and Mesopotamia were not using the tropical zodiac (it hadn't been invented yet), and so they had no need to establish a fixed reference point from which it could commence. But they were concerned with astronomical measurement of the cosmic points that indicated seasonal change, and they placed a heavy investment in their astrologers to keep their yearly cycles up to date by reference to the stars.

The problem of creating a fixed beginning to the zodiac really arose during the Classical period, when astrologers became as much philosophers as observers, more dependent upon mathematical divisions than direct observation of the stars, and less willing to invest in individual attention to the sky as reference to older tables set up by the astrologers who went before them. Supported by a workable calendar and a regulated society, there was little need to pay such close attention to this slow and almost imperceptible cycle of seasonal change. A cultural shift was moving the astrological focus of attention away from monitoring the movements of the stars, to philosophical questions such as, what are the stars, what are they composed of and what holds them in the sky?

After Alexander the Great united the three kingdoms of Egypt, Assyria and Greece in the 3rd century BC, the Hellenistic world arose, aiming to recapture the ancient philosophies of Egypt and Assyria and merge them into an integrated philosophical package that was to become part of the heritage of the western world. During this process, centers of learning were set up, where ancient manuscripts could be studied and the works compiled into a new standard of study. Classical, Hellenistic astrology underwent major modifications - it emerged in a very different form to that practiced in Mesopotamia or Egypt; the techniques were based upon earlier standards, but some philosophies were expanded and developed, some were lost.

During this process, knowledge of the shifting vernal point became obscured. The early astrologers of the Classical period came to regard the Vernal Equinox as fixed and stationary, falling somewhere in the early degrees of Aries. But there was clearly a great deal of confusion and debate as to where exactly in Aries it could be found. Manilius, in the 1st century AD, writes of how unsettled astrologers were on the issue:

Some ascribe these powers to the 8th degree, some hold they belong to the 10th nor was an authority lacking to give the 1st degree the decisive influence and control of days. [4]

We know also of earlier accounts placing the Vernal Equinox at the 12th or 15th degree of Aries. [5] The early Classical astrologers had the means to understand the problem of precession, but they didn't have the philosophical interest, preferring instead to conceive of the heavens resting on four eternal, fixed points of power and support. Although Hipparchus (c. 190-120 BC), credited with discovering the precession of the equinoxes, provided indisputable evidence of the phenomenom during the process of correcting earlier star charts, many of his contemporaries dismissed his findings, reluctant to relinquish their traditional beliefs. Hence, even as late as 77 AD, we find the Roman Historian Pliny ignoring his discoveries, writing in his Natural History that the Sun 'changes its course' at the 8th degree of Aries, in complete disregard to Hipparchus's work. [6]



Notes & References:

  4 ] Manilius, Astronomica, (Loeb edition) Trans. G.P. Goold. Harvard/Heinemann; Bk.III, v.679-682. The 'authority' to which Manilius refers is presumably Hipparchus.
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  5 ] For example, Achilleus Tacitus, Isag. ad Arati, Phenom.; 23, p.54, v17ff' and Eudoxus (Hipparchus 2.1.18). For a review of the various vernal points see O Neugebauer, 'A History of Ancient Mathematical Atronomy. 3 Parts'. Studies in the History of Mathematics and Physical Sciences, Vol. I.Berlin/ Heidelberg /New York: Springer-Verlag, 1975; p.593ff
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  6 ]
"The Sun has four differences, as there are two equinoxes, in spring and autumn, when it coincides with the centre of the earth at the 8th degree of Aries and Libra, and two changes of its course, in the 8th degree of Capricorn at midwinter when the days begin to lengthen, and the same degree of Cancer at the summer solstice."

Pliny, Natural History, English translation by H. Rackham; Cambridge, Harvard University Press, Ch. II, v. XVII.
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Deborah Houlding has been studying astrology for over twenty years. An international demonstrator, teacher and writer, her articles have appeared in popular media and astrological publications around the world. Deborah edited the UK magazine, The Traditional Astrologer, whilst her book The Houses: Temples of the Sky, presents research on the history, development and traditional meaning of the astrological houses. Deborah specialises in horary and the traditional application of astrology. This article is adapted from an unpublished work and may not be reproduced without permission.
© Deborah Houlding, 1997.
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History of the Zodiac
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