Nutation of the Earth

Further Information: The good news is that, as far as I can find out*, nutation doesn't actually affect the Movement of the Ages, as it doesn't change the overall rate of the Precession of the Earth. I've included it here because several, perhaps misguided, astrologers seem to think that it does.

However, if you are still interested in how nutation works see the diagram to the right.

* Disclaimer: however I am an astrologer, not an astrophysicist! I could be wrong.

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The Precession of the Moon's Orbital NodesThe plane of the Ecliptic is shown in gray. The plane of the Moon's orbit around the Earth is slightly tilted relative to it: by just 5°. As the Moon rotates around the Earth once every 27.3 days [a Sidereal Month] it spends half its time above the plane of the Ecliptic, and half its time below.

BUT just as the Earth's axis Precesses, so does the axis of the orbit of the Moon around the Earth. The effect of this is that the orbital nodes of the Moon [i.e. where the Moon's orbit crosses the Ecliptic] slowly rotate around the plane of the Moon's orbit around the Earth. The axis of the orbit of the Moon around the Earth completes one precessional circle once every 18.6 years, and therefore so do the Moon's orbital nodes. This is what causes the slight nodding of the Earth's axis over this 18.6 year time period.