Learn how to use the lensatic compass used by the US Military. PRECISION COMPASS. * LENSATIC *. PROVEN • RUGGED ACCURATE. CAMMENGA. FAX ( ANILINE AVE. HOLLAND, MICHIGAN I get lots of questions via email from people wanting to know how to use a lensatic compass, and I think I’ve covered that pretty well in a series of two posts.
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An agonic line runs through the U.
In addition to degrees to measure directions in a circle, the kensatic also uses 6, mils. If you don’t, visit the page just hyperlinked.
Lensatic Compass Guide
If you have help a party of threea chain tape is easy to use. You need to write things down, draw lines, perform math, and make sure you do so with a reasonable degree of accuracy. Tilt the lens bracket approximately 30 degrees from the perpendicular position of the compass.
Hold it square and straight in front of you like you mean business. When you sight a distant object, the magnetic bearing can be read from the dial to an accuracy of a degree or two, with care. The lensatic compass is used by the U. Now draw a line between the two points on the map, and determine the true bearing with a protractor.
Declination is extreme and rapidly changing with position in polar areas, making the compass worthless as a navigation aid there.
Proceed to that target.
How to Read an Engineer Compass | Sciencing
On the other hand, the records may vary irregularly by small amounts over times of hours, and these days are called disturbed days. How to Calculate Azimuth. Turn the compass in a horizontal manner until the azimuth is directly beneath the black index line on the face. The total intensity F of the geomagnetic field is now quoted in nT nanoteslawhich were once called gammas. In the southern temperate zone, point the 12 in the direction of the sun, and then north is halfway between the 12 and the hour hand.
In the last article we talked about declination, and how magnetic north and true north will vary depending on location and surrounding features. Hold the compass with your thumb fully in the thumb ring, and your index finger wrapped around and gripping the circular part of the underneath of the compass’s base. Lensatic Compass gives an introduction to the use of the compass.
This can be done, for example, before beginning the enginer hike, and the compass will then be useful in conjunction with the map. One advantage is it’s probably more accurate when it comes to “shooting azimuths,” meaning the act of determining the specific compass direction to a spot on the earth. The resulting increased ionization in the upper atmosphere, combined with tidal and wind motions, induces currents that create the extra magnetic field.
The perpendicular distance from the road to Antelope Hill is b sin A or a sin B, which gives ‘. We’ll start from the beginning, and go through everything you need to know to find your way over the terrain.
I, Elementary Surveying11th ed.
The mils are in black, and are the outer measurements on the ring. In the northern hemisphere, the field points downward to the north, so the south end of the needle must be weighted. This is a low level radioactive isotope that is used in a multitude of applications where self-powered illumination is necessary. Ionospheric currents also affect the magnetic field on a diurnal basis, and during magnetic storms, but the effects on a compass are smaller than the usual errors of measurement.
The effects of iron ships on the compass needle, with their permanent and induced magnetism, are very complicated to describe and have been the subject of much study. The field manual carefully illustrates soldiers using a compass without helmet lnesatic rifle.
The classical engineer’s transit had a compass in its base. Sometimes even a metal belt buckle can interfere with a compass, which can result in an incorrect reading. Keep doing this until you get to where you want to go. Be sure you understand magnetic declination. Orienteering is a competitive hiking hobby of some fame, of which I have only sketchy knowledge.