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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That line should intersect reasonable close to where the other lines crossed. Some of the components’ terms are used in the explanations below. It is not necessary to use the declination.

Lensatic Compass

The field manual carefully illustrates soldiers using a compass without helmet or rifle. Return from Lensatic Compass to Home. Open the compass lensayic and hold it level in front of you.

Then, you place your 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 amnual map. 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.

One reason for studying them is that ionospheric conditions have important effects on radio communications, and the magnetic variations are indicative of ionospheric conditions and “space weather” in general.

You can’t take bearings with a GPS receiver, either. Hold a compass level and steady to prevent the needle from touching the sides of the globe or the dial face. Now, hold the compass level and squarely in front of you. Use the engineer compass to measure the azimuth to take a bearing or direction.

At the 24 year mark it will be another half of that, and so on. If the tritium in your compass engineeer become dim such that you can’t read the compass at night, you can “charge” it up with any flashlight.


Declinations can be obtained in this way. Let’s say compaass see a water tower off in the distance. The compass was mounted on a tripod, enngineer a plumb bob could be attached to set it accurately over a point.

Lensatic Compass Guide

Lensattic, The Principles and Practice of Surveying: 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 difference between the bearings will be the declination.

There’s a lot of room for error and mistakes, and it takes time, which is sometimes a very precious commodity. 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.

This means that at around the 12 year mark, the tritium in your lensatic compass will have radiated about half the energy that it has to offer. Most mid-latitude inhabited areas have smaller and more regularly varying declinations. Their exact nature and cause are unknown.

The lid of the compass opens up to provide a slot with a crosshair as the front sight. Distances like this can be determined from the map, or from a vehicle odometer, if great precision is not required. In your case, however, your declination is degrees West, meaning you’ll have to add degrees before you set your compass. The Pacific is a region of easterly declination, the Atlantic of westerly.

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.

A lensatic compass weighted for the northern hemisphere will not work in the southern hemisphere, and vice versa. Using your protractor or other straight edge, you draw a line from your current position in the direction of where you want to go.


The reference direction and sense of measurement must compasw stated, by using compass directions or quoting it as an azimuth. Note the red number on the dial, which is the degrees under the black index line on the compass face.

Except along agonic lines, the needle points east or west of true north, and this is called the declination. When you make a closed fngineer, there is a check on the bearings and the pacing the traverse should close.

To find directions from your map, you’re going to need a protractor, a special instrument used for measuring angles.

This procedure can be rendered accurate enough for critical use by considering the actual position of Polaris and using a transit, but just assuming that Polaris is N will be satisfactory for compass work.

See any surveying text for how to find the area from the rectangular coordinates of the points. A web source of such a map is given in the References. All you do is take you compass and line it up from your current point to your desired destination and look at the compass reading.

Using a Lensatic Compass

The results are shown in the diagram. Hold your compass in the two-hand hold, steady and level in front of you. Next, rotate the entire compaws map and compass until your compass is telling you that it’s pointing north. Point of Interest An “azimuth” is pretty much the same as a “bearing.

Typically these features are prominent, such as a hilltop, a man-made structure, or an intersection, but they can engijeer more nebulous if you’re in a tight spot. Be sure you understand magnetic declination.

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