How to Use a Military Lensatic Compass? – Detailed Guide

Written by

John Cotton

FACT-CHECKED BY

Logan Miller

how to use a military lensatic compass

The center-hold and compass-to-cheek techniques are the two predominant methods of using a lensatic military compass. Differentiating which of the two techniques work better will mostly depend on your preference, compass-reading proficiency, as well as the environmental conditions you are in.

Understandably, the task of reading compass directions may be quite difficult for beginners. Without a map or its digital counterparts, finding the right direction to go can be intimidating.

So, here is a guide that will teach you how to use a military lensatic compass. Read on!

Steps to Use a Lensatic Compass

engineer-directional-compass

What to prepare

  • A lensatic military compass – Quite obviously, to learn how to use military compass, you’ll need your very own compass. It would be best to practice with a lensatic one, since it is known to be one that gives the most accurate directions.

If you are intending to use the compass under extreme environments, such as underwater or in very dark environments, you might be better off using a military prismatic sighting compass. It doesn’t require precise alignment like the lensatic type.

Step 1: Get familiar with the parts of a lensatic compass.

The compass is composed of many parts, each with a unique purpose. A lensatic compass is not your typical compass with magnifying glass; it is a more complicated instrument.

So, in order to fully understand how to use a sighting compass, you must be very familiar with its parts and their functions. Refer to our discussion below for more info.

Step 2: Choose your reading technique

As mentioned in the introductory portion of this article, there are two predominant compass-reading techniques: (1) Center-Hold Technique and (2) Compass to Cheek Technique.

The most apparent difference between the two is the positioning of the compass. The former involves laying the compass flat, in a 180-degree position, while the latter involves a 90-degree positioning of the compass.

More differences between the two are below:

 01 Center-Hold Technique

military-prismatic-sighting-compass

Between the two, this technique is considerably easier and more accessible. When environmental conditions are not very favorable, most prefer employing this technique.

Again, the compass must be fully-opened in a 180-degree position. The eyepiece should be slid upright, 90 degrees from the compass base.

Place the index finger of one hand alongside the base while the other fingers hold the compass steadily.

The thumb on the other hand should be between the rear sight and the bezel ring, while its accompanying index finger should be on the compass’s side (just like the other hand). Place the rest of the fingers under the base as in the last image above.

Determine the direction of travel, or azimuth, by pointing the cover of the compass (along with your whole body) towards your desired direction.

The azimuth is the value directly below the fixed index line.

 02 Compass-to-cheek Technique

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This technique may be more complicated to execute; however, it also delivers more accurate results. As mentioned, the compass is to be set in a 90-degree position, with the compass cover opened halfway.

The eyepiece should be bent forward in a 45-degree angle.

Hold the compass with one hand, making sure the index finger is curled around the device. Put your other hand over the one holding the compass.

Hold the compass close to your face and peek through the rear sighting slot while pointing to your desired direction.

Remember to rotate your whole body, not just the compass, when adjusting the direction you’re moving the compass to. Read the azimuth once you’ve successfully done this step.

Step 3: Take note of your readings

Ofcourse, you didn’t go through all that trouble just to forget your recordings! Make sure to take note!

Other Tips to Use a Military Lensatic Compass

Professionals recommend orienting the map before use in order to ensure you get accurate results. You need to have a USGS topographic map for this.

Compasses always point to the magnetic north. The magnetic north differs from the true north, thus the need for calibration.

Place the USGS topo map on a flat surface; make sure to lay it horizontally. Set north at your index line.

Look for a declination diagram on the map, and adjust the compass by rotating its dial. Line the compass up with a map line and turn the map until the needle’s inside the orienteering arrow.

Parts and Functions of a Military Lensatic Compass

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Before following the lensatic compass instruction, you must first familiarize yourself with its parts. There are three major parts of the compass.

These major parts contain smaller parts, which will be identified and discussed in this section.

1. Eyepiece

The eyepiece holds both the lens and a rear sighting slot. The lens is a magnifying glass that helps you read the compass dial.

The rear sighting slot is a small slit found on top of the lens; it helps direct eyesight when reading the compass.

The eyepiece doubles as a lock which clamps the compass cover and base together when not in use.

2. Compass Cover

The compass cover protects the more sensitive and breakable parts of the compass when they’re not in use. It also holds the sighting wire and sighting dots, which help in compass reading.

  • Sight Wire – The sighting wire is the vertical wire found within a rectangular slot in the middle of the compass cover. It is used as reference when determining direction.

On both ends of the rectangular slot, there are luminous sighting dots to aid in compass reading.

3. Base – The base serves as the body of the compass which holds numerous important parts, such as the following:

  • Thumb Loop – The thumb loop serves as a holder where you can slip in your thumb to position the compass when sighting the azimuth.
  • Compass Dial – There are two floating scales in a compass. The outer scales (usually in black font) are for mils, and the inner scales (usually in red) are for degrees.
  • Luminous and index lines – There are two lines on a lensatic compass. One is a luminous line that assists in navigation, especially when the compass is used in conjunction with a map or when in the dark.

The other is a fixed black line that is used as a reference demarcation when reading the compass.

  • Bezel Ring – This is found on the outer surface of the base and can be turned to change the orientation of the compass.

Frequently Asked Questions (FAQ’s)

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What is a lensatic compass for?

A lensatic compass can be used to set the course of travel. In using it, the azimuth is first determined in order to guide the traveler on how to proceed.

Aside from direction of travel, the lensatic compass can also be used to orient topographic maps by adjusting its declination.

Lensatic compasses are widely used in the military, but they have also proven their usefulness in outdoor recreational activities.

How do you read a military compass?

As mentioned in the previous section, a lensatic compass can be read through the center-hold or compass-to-cheek techniques. Essentially, it functions similarly to an engineer lensatic compass or engineer directional compass.

Conclusion

With this knowledge on how to use a military lensatic compass, hopefully, you are now better equipped to navigate and weather the challenges of the great outdoors.

Knowing how to read a compass is very important. It’s a useful survival skill not only to the uniformed personnel of the military but also to those who enjoy traveling.

Make sure to pass on this skill to your family and friends as well.

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