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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Copyright Leaf Group Ltd. Get your own customized topographical maps, built according to your specifications. See any surveying text for how to find the area from the rectangular coordinates of the points. When cmopass, use a map to help you navigate unfamiliar terrain.
Take your lensatic compass and open it up all the way so lenssatic is one flat line. To find directions from your map, you’re going to need a protractor, a special instrument used comlass measuring angles. To check your process, and even add a little more accuracy to it, find another feature and perform the same steps. Open the compass completely and hold it level in front of you. When you make a closed traverse, there is a check on the bearings and the pacing the traverse should close.
Learn Land Navigation Now. Do not move your head, but raise and lower your eyes when taking the azimuth using an engineer compass.
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.
Be sure you understand magnetic declination. That’s the heading that you need to move along to reach your desired end or way point. F varies from about 0. If you have a topographic map of your area, the declination can easily be determined by direct measurement. Pocket compasses seem to come in three forms, the lensatic, the mirror or Brunton q.
Declinations can be obtained in this way. But not to you, I trust.
If you have help a party of threea chain tape is easy to use. Put that hand up to the compass, steadying the compass by placing your index finger along the compass’s side, and wrapping your thumb between the bezel ring and the rear sight. To do this, we stop at road intersection and measure the bearings to the west peak of Antelope Hill, and to road intersection that is, along the road.
The compass was mounted on a tripod, and a plumb bob could be attached to set it accurately over a point.
Open the cover completely and pull engneer the rear sight. The perpendicular distance from the road to Antelope Hill is b sin A or a sin B, which gives ‘. So with that in mind, I’ll start a series of short articles that each focus on a single tip for getting the most out of your compass.
Lensatic Compass gives an introduction to the use of the compass. Then, you place lensatlc protractor on the map with its center point at your current position, making sure the north-south lines on the protractor line up with the north-south lines on the map. A plot of the traverse can then be made, and the enclosed area calculated.
We’ll start from the beginning, and go through everything you need to know to find your way over the terrain. If you examine the measurements of the field, on some days the records are smooth and only slowly varying. Turn the compass in a horizontal manner until the azimuth is directly beneath the black index line on the face. The lensatic compass is lensatoc by the U. William Gilbert, Queen Elizabeth’s physician, conceived the earth as a permanent magnet around Some speculations on the origin of the main cmpass are discussed in Geomagnetism.
Hold it square and straight in front of you like you mean business. A soldier egineer lots of iron around him, in his helmet and rifle for example, so these had to be put aside when using the compass.
Lensatic Compass Guide
Depending on which text editor you’re pasting into, you might have to add the italics to the site name. You want to find your position using the technique of partial resection, so you need to know that tower’s bearing with a high degree of accuracy. The directions of true and magnetic north are indicated on the sketch.
After reading those two articles anyone should be able to go out and perform basic land navigation with a map and lensatic compass.
The reference direction and sense of measurement must be stated, by using compass directions or quoting it as an azimuth. There may be a good site out there, but some I tried had vanished, and the rest were by people who would like to sell you a compass. Magnetic and true bearings lnsatic by the declination. Keep your head still and then read the azimuth through the lens bracket.
These variations are caused by ionospheric electron currents at altitudes of about km, and result from sun-earth interactions.
Whenever you can occupy both ends of a line, it is good practice to take both forward and back bearings, not only as a check, but also to determine if there is local deviation. The normal method to transfer angles from your lensatic compass to your map and back is with a protractor and a pencil.
Using a Lensatic Compass
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. It is magnetictrue or grid when referred to magnetic north, geographical north or grid north, respectively. If you don’t, visit the page just hyperlinked. Use the engineer compass to find the direction by lining up the compass with an object.