US Army M-1950 Lensatic Compass
This is a photo of the U.S. Compass, Lensatic, M-1950. The compass pictured was manufactured by Lee and StemWedel, Inc. of Chicago, IL, 11-1951. This model of the Lensatic Compass is essentially the same as the ones still in use in the 21st Century by U.S. forces. More detail on the Lensatic Compass is on the linked Olive-Drab.com page.
Since September 1992, the lensatic compass has been produced with tritium luminous markings for the U.S. Government by Cammenga, identified by NSN 6605-01-196-6971. It can be purchased from Amazon.com
at this link.
The following description is from FM 21-26 Map Reading, dated March 1956.
Lensatic Compass. The name is derived from the magnifying lens which is mounted in the eyepiece. The case is aluminum and the dial capsule is incased in a silicone rubber cap that automatically seals itself when it is assembled into the compass case. The compass case is about 2 inches long and less than 1 inch thick when closed. This compass has a 4 3/4 inch straightedge in the form of a graduated scale permanently attached with the straightedge parallel to the line of sight. Half of this scale is cast with the case and half with the cover, and connected with a hinge. Open, it is seen to be graduated in 100-metre units at a 1:25,000 scale. The dial of the compass is marked in 5-degree and 20-mil graduations. Magnetic azimuths can be sighted through the lens and sighting wire, and read accurately to within 2 degrees. Closing the compass automatically lifts the magnet and dial assembly off the pivot, thus protecting the parts from wear when the compass is not in use. Cardinal points and markings on the bezel crystal are luminous for reading in darkness. The north-seeking end of the magnetic needle is also luminous. A luminous area in the damping shell further aids in reading in the dark.
The lensatic compass is suitable for military units for reconnoitering, determining direction, orienting maps, fire control and other uses where magnetic azimuths are required.