Which compass is the clear winner? Knowing the differences between the two can save your ass outdoors.
Boring Basics You Should Know
There’s more to using a compass than pointing north and following it. Did you know that your compass can screw you over if you’re unaware of True North, Magnetic North, Grid North and Declination? In other words, north isn’t always north! Anything more than a few degrees off your target can result in fatal consequences.
You should understand the boring basics of True North, Magnetic North, Grid North and Declination. True North is the actual direction to the North Pole. Magnetic North is the magnetic field’s indication of north and it varies. Grid North is a map’s indication of north. Declination, known on maps as the “isogenic line,” is the degree variance between True North and Magnetic North; the degree differs according to your location. When you take a reading with your compass using north, you must take into account declination and re-orient north by adding N declination degrees east or west. The world map below displays isogenic lines according to your location:
Compasses: Let the Battle Begin
Baseplate: the compass is encased in a baseplate. An azimuth (arrow needle) stays affixed while you rotate the degree dial until 0 degrees match the red line indicating north. Other compasses have moving azimuths that you must line with the magnetic field to find north. Although they fit snugly in your pocket or hang around your neck, the majority of baseplates lack convenient reading features. Oftentimes you’ll find yourself manually calculating for declination.
Lensatic: although slightly bulkier and longer than baseplates, they’re packed with convenient features for taking accurate readings. The compasses are designed for and used by the U.S. military since World War 2. They’re defining highlight is the rear lens which make it easier to view degree readings. Plus you can automatically set declination. A small tritium light, which lasts between 10-24 years, permits you to view readings in darkness. There’s no dial to rotate—simply turn and point to find north. Separate millimeter markings are useful for calculating artillery targets. You even have two methods for taking readings: Center-Hold and Compass-to-Cheek (preferred army technique; within +/- 3 degrees of accuracy). Most lensatic compasses are encased in aluminum frames for longer durability.
Lensatic Compass! For all the reasons stated above.
Explaining how to use a lensatic compass (or any type) requires more time and space than this writing permits. Here are some additional websites you can read to learn more about military lensatic compasses:
- Trails.com Article: How to Use a Lensatic Compass
- Lensatic Compass Guide
- Understanding the Compass (Art of Manliness)