Definition
The celestial poles are the two points where the extension of Earth's rotation axis meets the celestial sphere. Stars near a pole describe small circles — they never rise or set for observers at mid-latitudes.
Precession and Polaris
Precession moves the north celestial pole in a 26,000-year circle on the sky. It was near Thuban in 3000 BC and will be near Vega in 14,000 AD. Today it lies close to Polaris (α Ursae Minoris).