Either of two diametrically opposite points at which the extensions of the earth's axis intersect the celestial sphere ... north to a point about 1û from Alpha Ursa Minoris (Polaris), and south to a point about 1û from Sigma Octantis (a fairly dim star sometimes called Polaris Australe). Often referred to as the north pole or south pole. The tilt of the Earth's axis causes the celestial pole above our planetary pole to describe a great circle in the sky over long periods of time. In 4500 BCE, Thuban, a star in the tail of Draco, marked the celestial north pole. This pole has, over time, shifted to Polaris and in about 12,000 years will shift to Vega
These are simply the projections of the Earth's poles, onto the celestial sphere. The declinations of the North and South celestial poles are 90°N and 90°S respectively. The star Polaris is very close to the North celestial pole. The poles provide an easy way of measuring latitude. Simply, the angle between the pole and the horizon, in degrees, is the equivalent to your latitude. See also celestial equator.