How to Use a Compass to Find a Magnetic Azimuth

An azimuth is a horizontal angle measured clockwise from a base line in degrees or mils. The baseline for the magnetic azimuth is magnetic north. The observer finding the azimuth is imagined to be at the center of a circle divided into 360 degrees or 6,400 mils, a measurement system used by the military.

A lensatic compass is commonly used for finding a magnetic azimuth. It consists of a floating compass dial that indicates magnetic north and is marked in degrees and mils, a lens that allows the observer to read the azimuth on the floating compass card without taking his eye off the target, a thumb loop to help hold the compass steady, and a black index line to indicate the magnetic azimuth.

Magnetic azimuth is used in the popular sport of orienteering. There are two methods of using the lensatic compass to find a magnetic azimuth: the center-hold method and the compass-to-cheek method.

Things You'll Need

  • Lensatic compass
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Instructions

  1. Center-Hold Method

    • 1

      Open the compass cover all the way.

    • 2

      Put a thumb through the thumb loop and use your middle and ring finger to form a steady grip. Place your index finger along the side of the compass.

    • 3

      Rest the thumb of the other hand on the compass between the eyepiece and the lens, and your index finger along the same side of the compass. Wrap your other fingers around the fingers of the other hand. Draw your elbows tightly to your sides to steady the compass.

    • 4

      Turn toward the target and point the compass cover directly at the target. The magnetic azimuth in degrees or mils is read off the compass card below the fixed black index line.

    Compass-to-Cheek Method

    • 5

      Open the cover of the compass to a 90-degree angle and the eyepiece to a 45-degree angle relative to the base.

    • 6

      Put a thumb through the thumb loop. Steady the compass with your middle and ring fingers and place your index finger along the side of the compass.

    • 7

      Raise the compass to your face and rest the thumb loop thumb against your cheekbone.

    • 8

      Observe the compass dial through the lens. Move the eyepiece up or down until the dial is in focus.

    • 9

      Line up the target with the sighting slot in the eyepiece with the sighting wire of the cover. Read the magnetic azimuth from the compass card under the index line through the eyepiece.