Keeping Time with Earth's Axial Precession

Zodiac Wheel 26000 Year Cycle

Greek astronomer Hipparchus of Nicaea was the first person to compare celestial observations recorded centuries apart. He noticed that the positions of stars appeared to gradually shift. Around the year 130 BC, Hipparchus used ancient observations from the Babylonians, Meton of Athens (fifth century BC), Eratosthenes, and others, and compared them to his own. He concluded that in the preceding 169 years those intersections had moved by 2 degrees.

The ecliptic and celestial equator intersect at the spring and autumn equinox points. The ecliptic and celestial equator intersect at the Spring and Autumn equinox points.

He was able to measure this change by comparing readings taken during one specific day of the year, the Spring Equinox. Twice per year, the durations of day and night are equal, and the Sun rises exactly in the east and sets exactly in the west.

Hipparchus concluded that the intersection marking the equinox slowly crept forward along the ecliptic, and called that motion "the precession of the equinoxes. " The rate is about one full circle in 26,000 years.

Zodiac Signs and Earth's Axial Precession

The Zodiac signs represent star constellations in our Milky Way galaxy as observed from Earth. A current zodiac sign is determined by drawing a line from Earth, through the Sun, and intersecting this line with one of twelve given star constellations. But this can also be used to determine larger celestial ages.

Axial Precession over 26,000 years.
Source: NASA

The Earth is currently inclined along its axis at an angle of 23.4° relative to its orbit around the Sun. But there is a wobble to this inclination. This is what Hipparchus referred to as axial precession. This precession takes roughly 26,000 years to complete, and traverses retrograde to the revolution of the Earth around the Sun.

Now pick one specific day of the year to observe the star constellation intersected by a line drawn from the Earth and through the Sun. For this day we will choose the Spring Equinox. In the northern hemisphere, the Spring Equinox (Vernal Equinox) currently occurs around March 20, when the sun moves north across the celestial equator. Days become longer than nights after this date.

Observing the Zodiac star constellation on this specific day for thousands of years will show the precession of the Earth about its axis. Over 26,000 years it will proceed throughout all twelve zodiac signs, as the date of the Spring Equinox gradually moves backward in the calendar year. These represent the Zodiac Ages. Using these concrete tools, we can then use a standard calendar spanning many thousands of years. And we can reconcile this with our own Modern calendars.


Our dating system is centered around the birth of Jesus, because that is the date we assign as the first year AD. It just so happens that the birth of Jesus coincides with the beginning of the Age of Pisces. Every year listed as BC is the number of years before this date, and years listed as AD are the number of years after this date. Thus, future calendar systems can be calibrated with our Modern calendar system by reconciling them with the beginning of the Age of Pisces.

The birth of Jesus coincides with the beginning of the Age of Pisces. This age is represented as two fish. It is curious that both early and Modern Christians use the symbol of a fish to represent their Christian faith.

It should be mentioned that in our Christian traditions, a sunrise service is held on Easter. These services are usually held outdoors, and the sunrise is observed. It is rather interesting that Easter falls shortly after the Spring Equinox in our Modern calendars.

The Sphinx

Sphinx during the Spring Equinox Sphinx during the Spring Equinox
Photo Credit: Santha Faiia

The Egyptian Sphinx turns out to be an excellent way to tell time over tens of thousands of years. On the Spring Equinox, the sun rises directly in front of the Sphinx. This permanent fixture on our planet's surface serves as an indication of which day of the year to choose to observe the current Zodiac age.

Supposedly the Sphinx was built around 2500 BC. But that would have been during the age of Taurus the Bull or right at the beginning of the Age of Aries (Ram). So you would think that the Sphinx would have horns. But it doesn't, the Sphinx is a lion, which would correspond to the Age of Leo. So perhaps the Sphinx was built around 9,000 BC, shortly after then end of the last Ice Age, or perhaps not.

The Zodiac Wheel

Below is a graphic of the Zodiac Wheel. It shows the star constellations intersected by a line drawn from Earth and through the Sun over the 26,000 year period of Earth's axial precession. The graphic can be used to determine the Zodiac sign throughout one calendar year, and also the Zodiac sign observed during the Spring Equinox. The beginning of the Age of Pisces represents the year 1 AD in our Modern dating system. The beginning of recorded history occurs around 4,000 BC, near the beginning of the Age of Taurus. The last ice age ended around 11,000 BC at the end of the Age of Virgo.

And God said, "Let there be lights in the expanse of the heavens to separate the day from the night. And let them be for signs and for seasons, and for days and years,"
Genesis 1:14

Originally published
Researched and Written by: Thomas Acreman

  The Babylonian Astronomical Compendium MUL.APIN by
   - NASA
   - NASA
  The Pyramids and Sphinx by

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Keeping Time with Earth's Axial Precession

  • Rick Boyd
    Sorry, but I do wish people who write articles mentioning astrology would go to the trouble of actually learning about astrology. The zodiac has nothing whatsoever to do with constellations, apart from the Greeks giving names to the signs from some of the constellations at that time. The zodiac was designed by ancient Babylonians, based on their calendar of 12 (and occasionally 13) lunar months, with 12 equal signs fixed to the March equinox. It has always been about the signs. The Western Tropical Zodiac will always begin with 0 degrees Aries on the March equinox and the stars have no relevance to this at all. The precession of the equinoxes and the alleged astrological ages are a minor oddity which astrologers generally have very little interest in.
  • Ray
    This article is about precession, which is obviously tangential to astrology, but the article never mentions the word. I'm not sure what you're going on about. The subject matter, especially in reference to constellations, is absolutely appropriate, as the ancients clearly were concerned about the positions of stars and planets, to think otherwise is absurd. The Egyptians understood the ages beginning and ending with certain star positions, whoever built the lion sphinx statue aimed it at Leo (the Lion CONSTELLATION), which tells us that it was likely built during that zodiacal age. I'm not sure how you can disregard the obvious tie-ins to key moments in history with what's marked out in the sky via constellations.
  • Michael
    If the stars have no relevance to astrology, what relevance do the planets have? Are the positions of the planets determined in relation to the “signs” as given by astrology, or are their positions determined in relation to their apparent positions relative to the ecliptic and the stars visible in that celestial band.? If we’re to disregard the apparent positions of the stars, why bother to observe the positions of the planets, either?
  • Anonymous
    Very understandable article , just what I was looking for as I have no background in astronomy. Thanks for your efforts.
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