Pole star Reference Libraries

Precession -- Precession is the phenomenon by which the axis of a spinning object "wobbles" when a torque is applied to it. The phenomenon is commonly seen in a spinning toy top, but all rotating objects can undergo precession. As a spinning object precesses, the tilt of its axis goes around in a circle in the opposite direction that the object is spinning. If the speed of the rotation...

Circumpolar Star -- Circumpolar stars are those stars which are located near the poles of the celestial sphere. As the Earth rotates, the sky appears to rotate; and most stars will be hidden below the horizon at some point in their circular paths. A circumpolar star is near enough to the celestial pole that it will never go under the horizon. It will therefore be visibile for all the night,...

Polaris -- Polaris, Alpha Ursae Minoris, is the bright star closest to the north celestial pole. It is also known as the North Star, the Lode Star, or the Pole star. Because it lies nearly in a direct line with the axis of the Earth's rotation "above" the North Pole -- the north celestial pole -- Polaris is apparently motionless from the Earth, and all the stars of the Northern sky appear...