True northTrue north
is a navigation term referring to the direction of the North Pole
relative to the navigator's position.
True north is compared to:
The direction of true north is marked in the skies by the celestial north pole. For most practical purposes, this is the position of Polaris
. However, due to the precession
of the Earth's axis
, true north rotates in an arc that takes approximately 25,000 years to complete. Currently, in 2002, Polaris is at its closest approach to the celestial north pole. 2,000 years ago, the closest star to the celestial north pole was Vega
On maps issued by the United States military, the U.S. Geographical Survey, and the U.S. Navy, true north is marked with a line terminating in a five-pointed star.