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Cammenga lensatic compass The M-1950 U.S. military lensatic field compass with self-luminous lighting (designated the Model 3H by Cammenga) is fitted with self-luminous tritium vial lighting. Under U.S. military specification (MIL-SPEC) performance criteria, ten pre-production samples of the M-1950 are required to meet a battery of performance ...
Classic geological compass (Brunton), sideview Classic geological compass (Brunton), topview. There are a number of different specialized magnetic compasses used by geologists to measure orientation of geological structures, as they map in the field, to analyze and document the geometry of bedding planes, joints, and/or metamorphic foliations and lineations.
Model of a lodestone compass from Han dynasty. Some claims state that the first compasses in ancient Han dynasty China were made of lodestone, a naturally magnetized ore of iron. [2] [16] The earliest mention of a needle's attraction appears in a work composed between 20 and 100 AD, the Lunheng (Balanced Inquiries): "A lodestone attracts a needle."
The pilot may use this pointer to home directly towards the beacon, or may also use the magnetic compass and calculate the direction from the beacon (the radial) at which their aircraft is located. Unlike the RDF, the ADF operates without direct intervention, and continuously displays the direction of the tuned beacon.
Tritium is found on several military models of compass that are sold to civilians (Silva of Sweden, Suunto, and Cammenga all make tritium models). Unlike radium-base paint, tritium gas emits only low energy beta particles (electrons) that are unable to penetrate the borosilicate glass walls of its capsule.
Silva Voyager compass (Brunton 9020) Silva Sweden AB created their first compass in 1928, and established their company in 1933. Below is a Chronological timeline of important dates in the history of Silva Sweden AB: [3] 1928 Gunnar Tillander invents the first orienteering (baseplate) compass. [4] [5] [6]
The liquid compass is a design in which the magnetized needle or card is damped by fluid to protect against excessive swing or wobble, improving readability while reducing wear. A rudimentary working model of a liquid compass was introduced by Sir Edmond Halley at a meeting of the Royal Society in 1690. [88]
A beam compass is a compass with a beam and sliding sockets or cursors for drawing and dividing circles larger than those made by a regular pair of compasses. [1] The instrument can be as a whole, or made on the spot with individual sockets (called trammel points) and any suitable beam.