Astrological Cosmology

Lascaux Planetarium (World Heritage Site)

In recent years, new research has suggested that the Lascaux paintings may incorporate prehistoric star charts.

The Dendera zodiac as displayed at the Louvre

The earliest Zodiac found in Egypt dates to the 1st century BC, the Dendera Zodiac.

The sculptured Dendera zodiac is a widely known Egyptian bas-relief from the ceiling of the pronaos (or portico) of a chapel dedicated to Osiris in the Hathor temple at Dendera, containing images of Taurus (the bull) and Libra (the scales). This chapel was begun in the late Ptolemaic period.

Temple of Hathor, Dendera

Vivant Denon drawing of Dendera Zodiac

His two-volume Voyage dans la basse et la haute Egypte ("Journey in Lower and Upper Egypt"), 1802, was the foundation of modern Egyptology.

He was appointed as the first Director of the Louvre museum by Napoleon after the Egyptian campaign of 1798–180.

During the Napoleonic campaign in Egypt, Vivant Denon drew the circular zodiac. In 1802, after the Napoleonic expedition, Denon published engravings of the temple ceiling in his Voyage dans la Basse et la Haute Egypte.

Sébastien Louis Saulnier, an antique dealer, commissioned Claude Lelorrain to remove the circular zodiac with saws, jacks, scissors and gunpowder. The zodiac ceiling was moved in 1821 to Restoration Paris and, by 1822, was installed by Louis XVIII in the Royal Library (later called the National Library of France). In 1922, the zodiac moved from there to the Louvre.

Zodiaque de Denderah with the 48 constellations of Claudius Ptolemaus clearly identified among the present 72 constellations on this Zodiac.

Ancient stargazers

Daressy or Cairo Zodiac

A "squeeze" or paper imprint of the now lost original, on display at the Louvre.

'Zodiac of Cairo' or the 'Daressy Zodiac'

Roman-period Greek zodiac that is loosely called the 'Zodiac of Cairo' or the 'Daressy Zodiac.' The grey marble plaque (also described as a disk or slab, and made of bronze) some 0.25 metre square was sighted by Georges Daressy in an antiquities dealer's shop in Cairo prior to 1901. (It has also been described as being found by Georges Daressy in (a) Cairo market at the beginning of the 20th-century.) Georges Daressy (1864-1938) was a leading French Egyptologist. The Daressy Zodiac remains one of the few extant examples of an Egyptian zodiac (Dodekaoros) from Roman times. (Another example is the 18th-century planisphere of the Italian philosopher and scientist Francesco Bianchini.) The Daressy Zodiac is now lost in that its present location remains unknown. What we have is a squeeze that was made by Georges Daressy. The squeeze is now kept in the French Archaeological Institute in Cairo.

The dodekaoros was a system of 36 "decans" according to which 3 "paranatellonta" were attached to each sign of the zodiac. Also, each zodiacal sign was divided into 12 equal parts or dodecatemories. The 'Daressy Zodiac' follows the Egyptian tradition in that it includes the dodekaoros.

Chinese Dodekaoros

Dodekaoros is a series of twelve animal patterns that express periods such as double hours, months and years. This has been used during the Greco-Egyptian period [1] and today in East Asia, especially China. The animals in the series are usually rat (or mouse [1]), bull, tiger, hare, dragon (or crocodile [1]), snake, horse, goat (or sheep [1]), monkey, rooster (or chicken [1] ]), dog and pig.

The archeological "theater" of Daressy.

Daressy spent 26 years in Egypt from 1866-1923.

planisphere of Bianchini

'Planisphaerium Bianchini') an astrological dicing board of the kind described by the Armenian Bishop Eustathius of Antioch. It involved divination by throwing and also served for casting horoscopes.)

The Babylonian MUL.APIN. Star Chart

MUL.APIN, Babylonian compendium that deals with many diverse aspects of Babylonian astronomy and astrology.

Babylonian astrology was the first organized system of astrology, arising in the second millennium BC.

The Babylonians used horoscopic astrology. By observing the seasonal movement of the sun, moon, and planets, the Babylonians connected their beliefs of divine intervention in their everyday life to space and time.

The five planets were identified with the gods of the Babylonian pantheon as follows:

Jupiter with Marduk,
Venus with the goddess Ishtar,
Saturn with Ninurta (Ninib),
Mercury with Nabu (Nebo),
Mars with Nergal.

The movements of the Sun, Moon and five planets were regarded as representing the activity of the five gods in question, together with the moon-god Sin and the Sun-god Shamash, in preparing the occurrences on earth. If, therefore, one could correctly read and interpret the activity of these powers, one knew what the gods were aiming to bring about.

(From left to right) Ashur, Ishtar, Sin, Enlil, Shamash, Adad, and Ishtar of Arbela are flanked by two star-worshippers

The calendar and astrology were very interconnected. When creating the calendar for the next month or year, it was important to keep in mind where important festivals and other religious activities would fall. It seems that four nearby, surrounding countries contributed to each twelve-month calendar year: Elam, Amurru, Subartu, and Akkad. The months were divided intro groups of three, alternating by four, evenly split among the four lands. The first, fifth, and ninth months belonged to Akkad, the second, sixth, and tenth belonged to Elam, the third, seventh, and eleventh belonged to Amurru, and the fourth, eighth, and twelfth belonged to Subartu.

Sumerian astrology tablet, dating from c. 2,300 BC)

Assyrian star planisphere from Assyrian Library at Nineveh (668-627 BC) British Museum.

Timaeus--the greatest Greek study of astrological cosmology, 360BC.

The Demiurge (creator-god) created the world out of the 4 elements: fire earth air water. He gave it the most perfect form and motion, a sphere rotating on its own axis...The CELESTIAL SPHERE which "appears" to rotate around us once a day.

Timaeus - birth of globe programming

The solar system modelled according to nested Platonic solids, J. Kepler, Mysterium Cosmographicum, 159

Three basic logical categories: Existence, Sameness, and Difference. When Demiurge created the WORLD, he gave it a soul. WORLD SOUL is a compound of Sameness, Difference, and Existence.

World-Soul is split into two halves: 2 bands laid island each other. These two bands of soul-stuff, tilted at an angle of 23.5 degrees, for the great circles of the EQUATOR, and the ECLIPTIC in the Celestial Sphere. Made to revolve.

EQUATOR: primary, outer band, single and undivided, the movement of the SAME.

ECLIPTIC: slanted, inner band, revolves contrary direction, called movement of the DIFFERENT. Subdivided into 7 unequal circles, forming the circles or spheres of the Sun, Moon, and planets. The seven circles correspond in ratio to the intervals of the musical octave (harmony of the spheres in the World-Soul).

...the structure of the heavens and the structure of the world soul are the same.

The Harmonic Sequence of the days of the week.

Plato’s “Phaedrus”--“The Allegory of the Chariot and The Tripartite Nature of the Soul”

All soul stuff in the World is one. Employing the highest intellectual faculties, the motion of the individual soul is united with the motions of the World Soul. To know SAMENESS = Equator. To know DIFFERENCE = Ecliptic/Planets.

After creating the planetary gods, Demiurge divides the leftover soul-stuff amongst the star -- us!

We each have our own particular star. Before incarnation, we were shown the workings of the cosmos. Contemplate the heavens to learn of soul-stuff.

PLATO'S IDEAS:

Ideal Forms. The signs of the zodiac signify the Ideas.

The Christian Aristotelian cosmos, engraving from Peter Apian's Cosmographia, 1524

The medieval Christian cosmology placed the heavens in a realm of perfection, derived from Plato's Theory of Forms

Based on the Aristotelian model, the Earth in the 'Divine Comedy' is at the center of the Universe, surrounded by whirling spheres made of transparent solid matter. Added to the Aristotelian eight spheres is a ninth sphere, the primum mobile or "first moved", the source of the movement of all the inner planetary spheres. Beyond the primum mobile lies the spiritual Universe, the mind of God or Empyrean heaven, thus this sphere marks the boundary between the natural and supernatural worlds.

Aristotle (384-322 BC), augmented Plato's mysticism with rational and causal explanation.

The Celestial Sphere is the most perfect Being, it's rotation initiated by the Creator--the First Motion (Primum Mobile)...ultimate source of all other motion. Yet doesn't account for the chaos below...yet still responding to heavenly cycles.

On the Heavens is Aristotle's chief cosmological treatise: written in 350 BC it contains his astronomical theory and his ideas on the concrete workings of the terrestrial world.

According to Aristotle in On the Heavens, the heavenly bodies are the most perfect realities, (or "substances"), whose motions are ruled by principles other than those of bodies in the sublunary sphere. The latter are composed of one or all of the four classical elements (earth, water, air, fire) and are perishable; but the matter of which the heavens are made is imperishable aether, so they are not subject to generation and corruption. Hence their motions are eternal and perfect, and the perfect motion is the circular one, which, unlike the earthly up-and down-ward locomotions, can last eternally selfsame. As substances, celestial bodies have matter (aether) and form (a given period of uniform rotation). Sometimes Aristotle seems to regard them as living beings with a rational soul as their form (see also Metaphysics, bk. XII). This work is significant as one of the defining pillars of the Aristotelian worldview, a school of philosophy that dominated intellectual thinking for almost two millennia. Similarly, this work and others by Aristotle were important seminal works by which much of scholasticism was derived.

(Typifies the fatalism associated with astrology...)

The Astronomica was written c. AD 30–40 by a Roman poet whose name was likely Marcus Manilius.

The earliest work on astrology that is extensive, comprehensible, and mostly intact, the Astronomica describes celestial phenomena, and, in particular, the zodiac and astrology.

—espouses a Stoic, deterministic understanding of a universe overseen by a god and governed by reason. (Little is known about Manilius except that he was a resident of Rome in the first century AD)

The Astronomica, which is written in hexameters, opens with Manilius contending that he is the "first to sing of astrology". He also claims that the god Mercury engendered his interest in celestial bodies.

The universe, as described by Manilius, is made up of two spheres: one solid (Earth) and the other hollow (the firmament), resembling this 17th-century depiction in Andreas Cellarius's Harmonia Macrocosmica.

In the first book he ponders the origin of the universe, considering theories by Xenophanes, Hesiod, Leucippus, Heraclitus, Thales, and Empedocles before arguing that the universe was created from the four elements and is governed by a divine spirit. According to Manilius, the universe is composed of two spheres: one—the Earth—is solid and the other—the "sphere of stars", often called the firmament— is hollow. The constellations are fixed in the firmament; the Earth is stationary and the firmament revolves around it, explaining the movements of the stars. The planets, the Moon, and the Sun also revolve around the Earth in the vast space between its surface and the edge of the firmament. Because the Earth is in the center of the universe, it is equidistant from the firmament and is thus not compelled to "fall" in any specific direction.According to Manilius, the universe is ruled by a god (conspirat deus) and is governed by reason (ratione gubernat).

Books two and three deal mainly with the finer details of the zodiac.

In this section, the poet briefly discusses the zodiac signs, the Olympian gods who serve as their protectors, and the relationship between the signs and the parts of the human body.

The Astronomica then considers dodecatemoria:

Dodecatemoria are subdivisions of the twelve signs of the Zodiac into a further twelve parts each. These can be said to form a "micro-zodiac" of 144 dodecatemoria, each corresponding to 2.5° of the ecliptic. In an alternate usage, the dodecamorion refers to a point on the ecliptic reached by the addition of twelve times a given number of degrees within a sign, either to the original degree, or to the beginning of the sign...originated in Babylonian astrology.

The Babylonian system was apparently adopted by the Greeks, who frequently attributed astrological knowledge to Chaldeans or Egyptians.The Latin authors Manilius and Firmicus both describe calculations of dodecatemoria. Ptolemy in the Tetrabiblos, however, dismissed the computation of dodecatemoria as illogical.

Abraham Ibn Ezra, a Hebrew scholar writing in the twelfth century AD, described two systems. In one system, attributed to Egyptian scientists and gentiles, a sign of 30° is subdivided into 12 sections of 2.5°, corresponding to a sequence of the seven heavenly bodies, with repetitions. In the other, attributed to Enoch and the Ancients, each degree within a sign corresponds with one of the twelve signs, starting with the sign itself. In the latter system, the cycle repeats two and a half times within each sign; for example, the dodecatemoria of Libra would begin with Libra in the first degree and return to Libra at 13° and 25°.

A Greek text (found in two existing codicies) connects the dodecatemoria with the homo signorum ("Zodiac Man") in which zodiacal signs are allocated evenly across the body from Aries at the head to Pisces at the feet.

King consulting doctor and astrologer

Vovelle to calculate the moon in the sign of the zodiac, John the Baptist and John the Evangelist (top) Cosmas and Damian bottom (medical astrology warns against surgery while moon in certain signs)

The last few lines (of Astronomica) are dedicated to an overview of the dodecatropos.

Most of the fifth (and final) book is a discussion of paranatellonta via the myth of Andromeda and Perseus.

Most of the work's fifth book deals with the myth of Andromeda (left), Perseus (upper right), and a sea monster (lower right).

Some astrologers that consult the stars refer to their affects as paranatellonta, or "paran" for short. Paranatellonta are stars that fall upon one of the four angles of the horoscope (rising or setting, at the midheaven, or at the imum coeli) at the same time a significant planet is at one of those points. Thus, for example, if Sirius was rising while Jupiter was at the midheaven, Sirius would be considered a paran of Jupiter and could influence the way the astrologer interpreted Jupiter in that horoscope.

The poem borrows or alludes to a number of philosophical traditions, including Hermeticism, Platonism, and Pythagoreanism but the prevailing belief of commentators is that Manilius espouses a Stoic worldview in the Astronomica. Stoics and Manilius agree on the divinity of the universe, the argument from design, the assumption that the supreme god is both the creator of the universe and the active force within it, the interconnectedness of everything, the understanding that humans are intimately connected to the cosmos, the importance of considering the heavens, and the belief in an inescapable fate that rules over all. The agreement on this latter point is of special importance because belief in fate is "one of the most notorious aspects of the Stoic system".

According to Greek, and later Roman mythology, the three fates determined the life span, represented by a thread, of each individual. Clotho spun the thread, Lachesis measured it, and Atopos cut it.

Zeno of Citium, the founder of Stoicism

Stoicism is a school of Hellenistic philosophy founded by Zeno of Citium in Athens in the early 3rd century BC. Stoicism is a philosophy of personal ethics informed by its system of logic and its views on the natural world. According to its teachings, as social beings, the path to eudaimonia(happiness) for humans is found in accepting the moment as it presents itself, by not allowing oneself to be controlled by the desire for pleasure or fear of pain, by using one's mind to understand the world and to do one's part in nature's plan, and by working together and treating others fairly and justly.

Manilius frequently imitates Lucretius, who wrote the didactic poem De rerum natura.

Manilius based much of his first book on portions of Aratus's Phaenomena.

Manilius diverges from his understanding of the cosmos; Aratus focuses on mythology and "graphic description", whereas Manilius emphasizes the scientific aspects of his work.

The Astronomica was rediscovered by Poggio Bracciolini c. 1416–17.

The sphere of Marcus Manilius made an English poem with annotations and an astronomical appendixby Sir Edward Sherburne (London : Printed for Nathanael Brooke, 1675)

This folio volume contains the first book of Marcus Manilius' Astronomicon, which is thought to be the oldest treatise on astrology, and a lengthy appendix by Sherburne.

The full version of the Astronomicon contains five books, the first on astronomy, and the remainder on astrology. The first book includes information on the constellations, planets, celestial circles and comets.

The frontispiece: This shows Pan on the left and Mercury (or Hermes) on the right with Urania, the muse of astronomy, floating above gazing at the heavens through a telescope. Pan is shown, somewhat unusually with wings, representing nature. Mercury (usually depicted with wings owing to his role as messenger) stands on a plinth inscribed 'university of interpretation' providing a connection between nature (Pan) and the celestial (Urania). Goold states, in his introduction to the Astronomicon:
'... the god Mercury simulated interest in the sky and paved the way for the ultimate discovery that destiny is written in the stars'.

Volcanic looking sun with sun spots and solar winds.

Surface of the moon and how it would look in it's four phases.

Vignette showing cherubs using various scientific instruments.

...this book also embodies a very specific agenda significant in the history of science in late 17th-century England: to promote modern astronomy and encourage its readership to provide financial patronage. An example of this is the paragraph at the end of the Catalogue supporting the new observatory at the University of St Andrews...using the method of 'Knowledge with delight'

'The Spheres, (which ever moving are) imply

That Arts and Learning, if unactive, die.

Our subject's Worth is by URANIA meant,

Our Poet's, PAN and MERCURY present,

Who sings rough Matter in smooth Verse, t'invite

The Ignorant to Learn, the Learn'd Delight'

Judicial Astrology

Before the Middle Ages, Platonic and Aristotelian cosmology founded the doctrine of correspondences and horoscopy. The word horoscope is derived from Greek words hõra and scopos meaning "time" and "observer" (horoskopos, pl. horoskopoi, or "marker(s) of the hour").

Established by 1st c. AD:

Natal astrology - horoscope of conception.

(INITIATIVES) - Katarche - a non-fated view, free will thru human choice.

Inception - start of a venture

Election - " "

Horary (Interrogation), moment a question is asked.

Decumbiture - for onset of illness

Ptolemaeus, Claudius, circa 83 AD - circa 161 AD, Greek scientist (mathematician), in the observatory of Alexandria, wood engraving, circa 19th century

Ptolemy, following Aristotle's ground plan, was the architect of the medieval universe until Copernicus, 1400 years later.

Tetrabilos, the "Four Books", brings Aristotle's scientific authority to judicial astrology, providing a rationale for horoscopes of conception and birth.

Tetrabiblos (Τετράβιβλος) 'four books', also known in Greek as Apotelesmatiká(Ἀποτελεσματικά) "Effects", and in Latin as Quadripartitum "Four Parts", is a text on the philosophy and practice of astrology, written in the 2nd century AD by the Alexandrian scholar Claudius Ptolemy(c. AD 90–c. AD 168).

The seasonal movements of the Sun due to the earth-sun annual cycle affect the ether, an essence suffused through heaven earth. This seasonal influence is represented in the differing qualities of the signs of the Zodiac. The four elements are also affected, and thru them every creature is influenced by the heavens.

Two orders of astrological effect:
Universal: producing periodic conditions - wars, famine, etc.
Particular: the most receptive moment when universal power of the heavens is indelibly impressed on the seed. I grows, manifesting the quality of that moment, unfolding in time in relation to the planets (the time keepers).
A naturalistic rationale for the horoscope of birth...horoscope of birth and conception correspond...a literal seed-moment, the true beginning in time, the causal-temporal origin of any creature.
Conflicts with the katarche (initiative) forms of horoscopy-- cannot be justified.
The moment a question is asked is not the causal origin of thing asked about.
Since Ptolemy, a tension exists between astrology as DIVINATION (katarche) and astrology as SCIENCE (natal astrology rationalized within the Aristotelian scheme).

The Arbatel De Magia Veterum (English: Arbatel: On the Magic of the Ancients) was a Latin grimoire of Renaissance ceremonial magic published in 1575 in Switzerland.
Waite assumes that the title is from the Hebrew: ארבעתאל‎ (or Arbotal) as the name of an angel the author would have claimed to have learned magic from....a reference to the Tetragrammaton, via the Hebrew ARBOThIM (fourfold) and AL (or God).

Perna printer's device & motto: Verbum tuum lucerna pedibus meisPs.119:105. "Thy word is a lamp unto my feet" 1558

...published by Pietro Perna, an Italian printer, the leading printer of Late Renaissance Basel, the Erasmian crossroads between Italian Renaissance humanism and the Protestant Reformation.

The Arbatel mainly focuses on the relationship between humanity, celestial hierarchies, and the positive relationship between the two. The Olympian spirits featured in it are entirely original.
Unlike other grimoires, the Arbatel exhorts the magus to remain active in their community (instead of isolating themselves), favoring kindness, charity, and honesty over remote and obscure rituals (of a Christian nature).
The Arbatel cannot be understood if separated from the philosophy of Paracelsus, who appears to have coined the term "Olympic spirits", and was the inspiration for the Arbatel's understanding of elementals(including Paracelsus's gnomes and the uniquely Paracelsian "Sagani"), the macrocosm and microcosm, and experimentation combined with respect for ancient authorities.
It was possibly the first work to use "Theosophy" in an occult sense (as opposed to a synonym for theology), and for distinguishing between human ("anthroposophia") and divine knowledge ("theosophia").

Polaris

Constellations along the Ecliptic
Zodiac takes 23 hrs, 56 min. and 4 seconds to revolve above us, Sidereal Day.

Constellations appear upside down to those in Southern hemisphere.

360˚ Ecliptic divided by 12 = 30˚ signs.
Sun takes 24 hours to revolve. Stars take 23.56.4 to revolve.
Therefore, every 30 days, the sun enters a new sign of the Zodiac.
Sun travels thus through the zodiac called a Solar Year.

Mainstream view of Zodiac:

As seen from the orbiting Earth, the Sun appears to move with respect to the fixed stars, and the ecliptic is the yearly path the Sun follows on the celestial sphere. This process repeats itself in a cycle lasting a little over 365 days.

The ecliptic is the mean plane of the apparent path in the Earth's sky that the Sun follows over the course of one year; it is the basis of the ecliptic coordinate system. This plane of reference is coplanar with Earth's orbit around the Sun (and hence the Sun's apparent path around Earth). The ecliptic is not normally noticeable from Earth's surface because the planet's rotation carries the observer through the daily cycles of sunrise and sunset, which obscure the Sun's apparent motion against the background of stars during the year.
Because Earth takes one year to orbit the Sun, the apparent position of the Sun takes one year to make a complete circuit of the ecliptic. With slightly more than 365 days in one year, the Sun moves a little less than 1° eastward every day. This small difference in the Sun's position against the stars causes any particular spot on Earth's surface to catch up with (and stand directly north or south of) the Sun about four minutes later each day than it would if Earth would not orbit; a day on Earth is therefore 24 hours long rather than the approximately 23-hour 56-minute sidereal day.

The plane of Earth's orbit projected in all directions forms the reference plane known as the ecliptic. Here, it is shown projected outward (gray) to the celestial sphere, along with Earth's equator and polar axis (green). The plane of the ecliptic intersects the celestial sphere along a great circle (black), the same circle on which the Sun seems to move as Earth orbits it. The intersections of the ecliptic and the equator on the celestial sphere are the vernal and autumnal equinoxes (red), where the Sun seems to cross the celestial equator.

Precessional movement of Earth. Earth rotates (white arrows) once a day around its rotational axis (red); this axis itself rotates slowly (white circle), completing a rotation in approximately 25,772 years. ( axial precession )

Hipparchus of Rhodes

The discovery of precession usually is attributed to Hipparchus (190–120 BC) of Rhodes or Nicaea, a Greek astronomer. According to Ptolemy's Almagest, Hipparchus measured the longitude of Spica and other bright stars. Comparing his measurements with data from his predecessors, Timocharis (320–260 BC) and Aristillus (~280 BC), he concluded that Spica had moved 2° relative to the autumnal equinox. He also compared the lengths of the tropical year (the time it takes the Sun to return to an equinox) and the sidereal year (the time it takes the Sun to return to a fixed star), and found a slight discrepancy. Hipparchus concluded that the equinoxes were moving ("precessing") through the zodiac, and that the rate of precession was not less than 1° in a century, in other words, completing a full cycle in no more than 36000 years...mentioned by Ptolemy, who explains precession as the rotation of the celestial sphere around a motionless Earth. (egocentricity)
The first astronomer known to have continued Hipparchus's work on precession is Ptolemy in the second century AD. He found that between Hipparchus's time and his own (about 265 years), the stars had moved 2°40', or 1° in 100 years (36" per year; the rate accepted today is about 50" per year or 1° in 72 years). He also confirmed that precession affected all fixed stars, not just those near the ecliptic, and his cycle had the same period of 36,000 years as found by Hipparchus.

Precessional movement as seen from 'outside' the celestial sphere

The 26,000-year cycle of precession as seen from near the Earth. The current north pole star is Polaris(top). In about 8,000 years it will be the bright star Deneb (left), and in about 12,000 years, Vega (left center).

Diagram showing the westward shift of the vernal equinox among the stars over the past six millennia
The precession of the equinoxes is caused by the gravitational forces of the Sun and the Moon, and to a lesser extent other bodies, on the Earth. It was first explained by Sir Isaac Newton.

Precession of a gyroscope.
Axial precession is similar to the precession of a spinning top. In both cases, the applied force is due to gravity.

Tidal force on Earth due to the Sun, Moon, or a planet, expressed by Newton's law of universal gravitation.

An astrological age is a time period in astrologic theology which astrologers claim parallels major changes in the development of Earth's inhabitants, particularly relating to culture, society, and politics. There are twelve astrological ages corresponding to the twelve zodiacal signs in western astrology. Advocates believe that when one cycle of the twelve astrological ages is completed, another cycle of twelve ages begins. The length of one cycle of twelve ages is 25,860 years.

Mark Knight's explanation:

The whole blanket of stars "wobbles", not the earth.
The Great Year.

The path of the Earth's North pole projected into the heavens describes a circle which takes 25,772 years to complete. The annotations in red indicate the position of the polar point in past epochs and the constellation in which the vernal equinox occurred at that time.