The Changing North Pole Star
Definition: [Astrological Ages] Because of the Precession of the Earth, over the period of a Great Year the north Pole Star changes. This is not because the stars are changing, but because our Viewpoint of the stars changes very slowly because of Precession.
Precession can be thought of as the slow movement of the Earth's axis with respect to the stars. Hence, as the axis is moving, with time it points to different places in the heavens. The dotted circle on the figure below shows all the places that the axis will point to over a complete Great Year. Back in 2700 BC the axis pointed to the star Thuban, the Snake; now it points to Polaris
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The Changing Pole Star How to understand this star map: Have a look bottom left, that's the date in years. It starts in 3000 BC, [the BC years have a minus sign in front] when astrology was just beginning amongst the Mesopotamian culture, and goes through to 8000 AD. As the years change the figure is showing you a picture of the night sky at the time. It stops momentarily at 2000 AD to show you the sky as it looks now. Next, have a look at the spot marked Zenith in the center of the star map. That spot marks the point in the night sky where - over the centuries - the North Celestial Pole lies. You can see that as the centuries pass, different stars are the star at the Zenith. [A dotted circular line has been drawn on the figure so you can see which stars will become the Pole Star as the centuries pass.] Currently, the star Polaris, α Ursae Minoris is the Pole Star. Back in 2700 BC the star Thuban, α Draconis, in the constellation of the Dragon, was be the Pole Star. This is one of the faintest stars in the sky to have a name, doubtless because it was of such importance to our astrological ancestors. |
Key Concepts...
| 2: | Key Concepts... |
| 2a: | Precession of the Earth |
| 2b: | Nutation of the Earth |
| 2c: | Movement of the Vernal Equinox Point |
| 2d: | Precession of the Equinoxes |
| 2e: | The Changing Pole Star |
© Dr Shepherd Simpson, Astrological Historian
Historical Astrology
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