An imaginary circle traced out against the sky by the Earth's Celestial Poles
(perpendicular to the Earth's Equator) around the
Ecliptic Poles (perpendicular to the plane of the Solar System).
Each Celestial Pole moves very slowly around its circle, travelling
about one degree every seventy years against the background of stars, under the
influence of precession. The Northern Pole
presently lies close to the star Polaris, making it the current