Compass Terminology

The following definitions are from the Brunton Instruments for Outdoor Adventure 2000 Catalog, Using a Map and Compass by Don Geary, and Orienteering, by Steven Boga.

Ý Bearing:  The direction of travel from your current position to a landmark or destination expressed in degrees from 1 to 360.

Ü Graduations: The series of degree markings (from 1 o -360 o, with 0o=N, 280 o =S etc.) on the compass ring used for taking bearings.

Þ Azimuth:  A degree bearing from your position to an objective.

Û Azimuth ring:  The rotating part of your compass that holds the damping fluid (which stabilizes the magnetic needle) and has degrees engraved around its edge from 1 to 360.  Note, the simpler compasses do not have the azimuth ring, but they do have the graduations marked.  A compass that says 1 o graduations, has each degree marked, 2 o has every other degree marked.  The lower the graduation, the higher the accuracy, some compasses mark only N, W, E, S or cardinal points.

Ý Declination:  The difference in degrees, or angle, between true north (the North Pole) and magnetic north (the region where compass magnets actually point, which is NOT the north pole or true north).  When you read a map, it is marked with true north.  To plan a route, you need to know how many degrees east or west your compass needle is actually pointing, and adjust you compass accordingly.  We indicate in our product descriptions which compasses are declination adjustable.

Ü Orienting Arrow:  The north/south pointing arrow engraved or painted into the housing used to center the magnetic needle when establishing a bearing.

Þ Direction-of-travel Arrow:  The arrow embossed on the base plate of an orienteering compass; used to indicate travel direction once the magnetic needle has been aligned with magnetic north.  For example, if you want to go west, you set the direction of travel arrow on west, then, holding the compass in your hand, rotate your body until the red end of the magnetized needle is lined up with the orienting arrow, you are then facing west.  Brunton’s Safari, Elite and Pioneer use a sighting line on the mirror rather than the direction-of-travel arrow.

Û Mirrored Compass:  A compass which allows the user to simultaneously sight and object and align the orienting arrow and magnetic needle.

Ý Lensatic Compass:  A compass which uses a retractable lens to read the bearing while simultaneously sighting an object.

Ü Clinometer (sometimes inclinometer):  The device that measures the difference in degrees or angles from level (0 degrees).

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