True North

True north (geodetic north) is the direction along the earth's surface towards the geographic North Pole.

True geodetic north usually differs from magnetic north (the direction a compass points toward the magnetic north pole), and from grid north (the direction northwards along the grid lines of a map projection). Geodetic true north also differs very slightly from Astronomical true north (typically by a few arc seconds) because the local gravity may not point at the exact rotational axis of the earth.

The direction of astronomical true north is marked in the skies by the north celestial pole. This is within about 1 degree of the position of Polaris, so that the star appears to trace a tiny circle in the sky each day. Due to the precession of the Earth's axis, true north rotates in an arc with respect to the stars that takes approximately 25,000 years to complete. In 2102 Polaris will make its closest approach to the celestial north pole. 5,000 years ago, the closest (visible to the eye) star to the celestial north pole was Thuban.

On maps published by the United States Geological Survey and the United States Armed Forces, true north is marked with a line terminating in a five-pointed star. The east and west edges of the USGS topographic quadrangle maps of the United States are meridians of longitude, thus indicating true north (so they're not exactly parallel). Maps issued by the United Kingdom Ordnance Survey contain a diagram showing the difference between true north, grid north and magnetic north at a point on the sheet; the edges of the map are likely to follow grid directions rather than true, and the map will thus be truly rectangular/square.

Other articles related to "north, true north":

Types of Compasses - How A Magnetic Compass Works
... A compass functions as a pointer to "magnetic north" because the magnetized needle at its heart aligns itself with the lines of the Earth's magnetic field ... needle, pulling one end or pole of the needle toward the Earth's North magnetic pole, and the other toward the South magnetic pole ... to die out, one end points toward the North magnetic pole ...
True North (Bill George Book)
... True North, by Bill George and Peter Sims, is a best-selling 2007 business book and follow-up to George's 2003 bestseller Authentic Leadership ... True North is part of the acclaimed Warren Bennis series of business books, and is published by Jossey-Bass, an imprint of Wiley publishing ...
Stephen Fearing - Solo Career
... Soon after, Fearing was signed to True North Records ... True North re-released Fearing's first two efforts Out To Sea and Blue Line ... Following the release of the album, he left True North Records after 20 years ...
Cleveland Browns Relocation Controversy - Effect On Teams in Other Sports Leagues
... After the Coyotes went bankrupt in 2010, an ownership group called True North Sports Entertainment tried to buy the team and return it to Canada, where it would have reassumed the Jets' name and history in ... The league elected to let True North use the name, but the new Jets were not able to use the old Jets' history as that would remain in Phoenix with the Coyotes ...
Murray Mc Lauchlan - Discography - Albums
... Chart Positions CRIA Label 1971 Song from the Street 38 True North 1972 Murray McLauchlan 1973 ... Day to Day Dust 1974 ... Sweeping the Spotlight Away 1975 ... Only the Silence Remains 39 1976 ...

Famous quotes containing the words north and/or true:

    The pure products of America go crazy—mountain folk from Kentucky or the ribbed north end of Jersey with its isolate lakes and valleys, its deaf-mutes, thieves.
    William Carlos Williams (1883–1963)

    ... if it be true that death is annihilation, then the man who believes that he will certainly go straight to heaven when he dies, provided he has fulfilled certain simply observances in this life, has a cheap pleasure which will not be followed by the least disappointment.
    Charles Sanders Peirce (1839–1914)