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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Putting the two in a opaque bag or enclosure is effective as well. The Brunton is well adapted to field geology.
Determining a Bearing, or “Shooting an Azimuth”. A compass is a floating magnetic needle that always points toward a magnetic north pole.
Using a Lensatic Compass
In the event that you’re under strict light discipline in a military setting, for example you can simply sup your hands around the compass and the head of the flashlight so that no light escapes. The results are shown in the diagram. How to Use the Engineer Compass. A forward bearing is specified from the point you occupy to the distant point, while a back bearing is in the other direction.
Lensatic Compass Guide
You can’t take bearings with a GPS receiver, either. To use your lensatic compass to find the direction of your intended azimuth which you probably got from your map, using your protractor:.
The intersection gives your position. With the thumb loop all the way down under the compass, put the thumb of one hand all the way inside the loop, and place the index finger of that same hand along one side of the compass.
This one will deal with night and low light navigation, a topic that could span several lengthy articles on its own. Whenever the luminous magnetic arrow lines up with the luminous short line, you’re following your intended azimuth. I guess the military needs the extra accuracy now and then say, for example, to precisely place artillery fire.
This is exactly the way land surveys were made in former days, except that a chain was used for the distance measurement. The back azimuth is nothing more than the opposite direction of the reading you’re taking.
The reference direction and sense of measurement must be stated, by using compass directions compasx quoting it as an azimuth. At that point you know what direction you need to head to get to your next stop, and if you pair that with an accurate distance you’ll be on your way in no time. Rotate the bezel on the face of the compass until the indicator is directly over the “north” position indicated by an upper case “N”. A soldier had lots of iron around him, in his helmet and rifle for example, so enginere had to be enguneer aside when using the compass.
These variations are caused by ionospheric electron currents at altitudes of about km, and result from sun-earth interactions.
Hold the compass level by your thumb and index finger. Make an “L” shape with manuao index finger and thumb of your other hand. The Law of Sines gives us the unknown sides: If you examine the measurements of the field, on some days the records are smooth and only slowly varying. Inexpensive compasses have only one cover glass with the two lines, which somewhat interferes with night use, though comlass preset bearing can be followed by lining up the long line and the compass north.
You then see where the line you drew intersects with the protractor’s numbers, in this case degrees. 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. The normal method to transfer angles from your lensatic compass to your map and back is with a protractor and a pencil.
As long as you can hold the compass level and steady, the exact grip doesn’t matter. The total intensity F of the fompass field is now quoted in nT nanoteslawhich were once called gammas.
The key to the whole operation is having a map and being able to locate these features on that map. Iron on or near one’s person is a fertile source of deviation.
The azimuth is the angular measurement of an object’s direction in relation to the viewer. These variations are discussed below. That’s the heading that you need to move along to reach your desired end or way point. From lensaatic direction of the field, they must circle the earth’s axis in a westerly direction. Close is good enough in horsehoes, but I’m hoping exact is the standard for artillery fire.
Steady the compass by allowing the hand holding the compass to rest in the cupped palm of your other hand. Before this, the odd properties of suspended or floating needles was known, but was not connected with direction on the earth, and was regarded as magical.
Some recent lensatic compasses have square cases with ruler edges, bringing them closer to orienteering compasses.
Two-hand Hold of the Lensatic Compass. The compass case has index marks at the top of the lid, and beneath the rear sight.
This works in the northern temperate zone. You don’t want to hold it crooked, cockeyed, or off level. There are luminous lines and letters on the dial and the cover glass that allow use in the dark, though bearings must be set previously in the light. The bezel clicks as it moves–three degrees for every click. The more back compase you can draw, the more accurate your location will be.
Return from Lensatic Compass to Home. Line up the sighting groove in the bracket with the wire and an object in the distance. ,anual draw a line between the two points on the map, and determine the true bearing with a protractor.