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Ruian Shunfeng Navigation Instruments Co.,Ltd

Add: No.20, Heping Road, Jinhu Street, Ruian, Zhejiang, China
Con: april Zhang
Tel: +86-577-65520898
Fax: +86-577-65966926
Mob: +8618158321811
Email: sale@rashunfeng.cn


How Accurate Is The Magnetic Compass?

As long ago as the 15th century, mariners noticed that the needle of a magnetic compass does not point accurately to Earth's true north. Columbus, for instance was aware of this on his voyages across the Atlantic in the 1490s. Instead, the needle makes an angle with true north, and that angle varies from place to place on the Earth's surface. This means that there is a different magnetic variation for different places on Earth. These variations were investigated on a famous 17th century voyage by the great scientist and astronomer Edmond Halley. It was thought at this time that the longitude of a ship could be found by the compass variation, but this proved to be untrue.