While scanning through the Internet search engines in 1996, I came across this web site found at http://www.technosophy.com/milltime.htm
(The following are highlights from this article, thus using the items specifically for information only in context with emphasis inserts to clarify certain elements.
Mr. Alden covers his subject very thouroughly and provided a good article for myself to reference to the 7-6 B.C. theory of the Star of Bethlehem, and also jumps into the future Age of Aquarius and its connections.)
The Sun, of course, circuits the Zodiac in one year and defines the seasons as it goes, so the year is bound to be one of the fundamental units or cycles of time. Saturn takes nearly 30 years and Jupiter nearly 12 years to complete their cycles. The numbers, 30 and 12, have clearly been very important in setting up our temporal and spatial units and coordinates.
Is it because Jupiter takes 12 years to move around the Zodiac that there are 12 constellations instead of some other number? Multiplying 12 by 30 gives 360, the number of degrees in a circle or a Zodiac of 12 signs of 30 degrees each. On the Equinoxes we have 12 hours each of daylight and night. The day has 24 hours (twice 12) of 60 minutes (twice 30) each. The number 360 is also close to the number of days in a year. The ancients had a calendar of 12 months of exactly 30 days each, the extra five days inserted between calendars being dedicated to the Lord of Misrule because they didn't fit in to the system. This was the festival period of the Saturnalia when the normal order was suspended and the fool was paraded as mock king.
Even the association of the Greek god Zeus with the planet Jupiter or Kronos with Saturn has been resisted by specialists in language, for example, specialism being another sign of the separatism and non-integration of modern science. Some have resisted the phonetic connection between the Greek name for Saturn, Kronos, and the root of English words related to time, such as 'chronic' and 'chronometer.'
Upsetting the divine order and regularity of the cosmos was an evil factor and this was associated with the phenomenon of the precession. This is the very slow gyroscopic wobble of the Earth in which its axis of rotation completes a circle in the sky in about 25,800 years. The motion causes the seasons of the year to very slowly get out of sync with the stars normally associated with those seasons.
This is because the effect is too small to be detected in one human lifetime without modern precision instruments. Our science doesn't say how Hipparchus discovered it without modern instruments, however.
But modern instruments are not, in fact, required -- only dedication and persistence in observing the major features of the heavens over long periods of time, at least a few centuries. This the ancients possessed in abundance. Festivals were held on the solstices and equinoxes. The spring equinox was particularly important. The Zodiacal constellation rising in the East before the Sun as night turned to dawn was memorialized in myth.
These celebrations went on year after year for centuries and precise astronomical records were also kept in many of the high civilizations of antiquity. After only a century or two, the changes due to precession would be noticeable to a trained astronomical priesthood. And after 2000 years a whole new constellation would be rising before the Sun on the Vernal Equinox. The Equinox point itself moves backwards through the Zodiac at a rate of about one degree in 72 years, or one 30 degree sign in about 2160 years. De Santillana believed that the ancients not only knew about the phenomenon but were virtually obsessed by it.
This is not to say that precession was understood in the terms we know today, involving a torque or force on the spinning planet from the gravitational pull principally of the Sun and Moon acting upon the uneven distribution of the planetary mass. It only means that they were well capable of observing its long-term effects. They also knew the length of the precession cycle to some degree of accuracy. Plato is said to have used a figure of one degree per century which is a bit too slow, but the excellent star watchers of ancient Babylon and Persia may have had a more precise value.
De Santillana suggested that the Zodiacal figure rising before the Sun on the Vernal Equinox held a special place in the religious worship of ancient peoples and was celebrated in ritual and storytelling during its tenure, on the average about 2160 years, before the next constellation took its place. The period of the precession of the Vernal Equinox Point backwards through one Zodiacal group is referred to as a World Age, and each figure so rising before the Sun (called helical rising) gave its name to the Age. In all of recorded history, covering a mere 6000 years, only three World Ages have taken place. These are the Ages of Taurus (about 4400 - 2200 B.C.), Aries (2200 - 0 B.C.) and Pisces, the current era (about 1 - 2200 A.D.). In the Taurean Age, according to de Santillana, the Bull was worshipped as the chief religious symbol. In the Arian, it was the Ram or Lamb, and, in the Piscean, it is the Fishes, though this practice has been mostly forgotten now.
The ancients observed everything going on in the skies and made records particularly of planetary motions which covered long periods. They discovered a peculiar cyclic pattern in the coming together of the planets Jupiter and Saturn which they called Great Conjunctions to distinguish them from the more frequent lesser conjunctions involving the other, faster-moving planets. Great Conjunctions occurred about every 20 years but every third Great Conjunction, in about 60-year intervals, occurred most often in the same constellation of the Zodiac.
The 20-year conjunction points are roughly one-third of the Zodiacal Circle around from each other. If the points are connected, they form a near equilateral triangle within the circle. Each successive 60-year Great Conjunction occurs an average of about nine degrees farther down the track, in the forward direction through the Zodiac, from the previous one. Therefore, the entire triangle can be thought of as rotating in the forward direction through the Zodiac in increments of nine degrees every 60 years. This grand pattern is referred to as the "Rotation of the Trigon of Great Conjunctions." Any one of the corners of the triangle or trigon will move through 30 degrees in about 200 years and completely around the Zodiac in 2400 years. These intervals were easily discoverable by the ancients with simple observational persistence and record keeping; no sophisticated instruments were required.
All that is needed to precisely mark the moment of the beginning of a New Age, however, is a unique but predictable event selected from a convenient and known system for breaking down world-age periods into smaller intervals. Here is how de Santillana believed it was done. The mythology prescribes a conjunction of Jupiter and Saturn "at the place of passage," meaning as close as possible to the location of the Vernal Equinox Point as it precesses into the next World Age constellation. This is all that is required, with some judicious reasoning regarding constellation boundaries, to identify the exact moment when a New Age might commence. The two hands of the Cosmic Clock must coincide.