Magnetic Deviation Meaning

Example : Used other than as an idiom: see magnetic,‎ deviation.1904, Ernest Rutherford, Radio-activity, Dover, 2004, page 117,  Preliminary experiments with radium of activity 1000 showed that it was very difficult to determine the magnetic deviation of the α rays.Magnetic declination.1998, John R. Ellis, Objectifying Real-Time Systems, page 483,  This angular difference is the local magnetic deviation (Figure C.2). Navigation systems normally work relative to True North and therefore must remove the local magnetic deviation.