The engineer lensatic compass is a precision instrument useful in measuring directions to objects and for land navigation. These compasses are not artillery compasses but are used in a very similar fashion. As the name implies, the lensatic compass employs a lens in the rear sight that allows precise readings of the dial. This precision is ineffective if the compass is improperly held or misused when taking an azimuth.
A lentastic compass is a modern compass which utilizes magnetized cards instead of a needle to point to magnetic north. What makes this kind of compass different from many other modern compasses is the lack of a clear plastic protractor for orientation on a map. Furthermore, the compass has been designed to determine the orientation of objects at a glance through the targeting receptacle. In general, orientation on a map using a lentastic compass is more difficult than with a compass with a built-in protractor.
- 1.Open the compass case completely so that you can see the compass. On the face of the compass is a card floating on a central pivot, with one end usually painted in red. This painted end points towards magnetic north. Turn yourself until you face the same direction as the needle. You are now facing towards magnetic north. If you need to travel in another direction, orient yourself from true north towards the direction that you wish to travel in. When looking north, west will be to your immediate left, south behind you and east to your immediate right.
- 2.Determine what direction you wish to travel in. Since walking with the compass in order to follow a direction is extremely difficult to do, it is better to determine a point to walk towards in the distance. To do this, find the targeting receptacle -- often the outermost case of the compass and built onto a hinge with a thin gap and a thin wire running through the center.
- 3.Move the targeting receptacle to a 90 degree angle from the compass face. A lentastic compass is designed so that you can look through the targeting receptacle to a point in the distance and glance down to determine what direction you are looking at.
- 4.Focus on an object in the distance that coincides with the direction you want to travel in. Once you have determined the object you will be traveling towards in the distance, you can use that object as a reference point to aim towards as you travel. If traveling a long distance, recheck your orientation every so often to ensure that you are still traveling in the correct direction.
- 5.Align the compass and the arrow pointing to magnetic north as closely as possible to indicate your orientation on the map. While this will give you a general orientation on a map, it is less precise than using a compass with a built-in protractor.