![]() We know to use the scale on the inside because the measurements are increasing as you move towards the line and they’re less than 90°. In the above image, the angle opens up to the right and is acute.The number that the ray passes through is your angle’s measurement in degrees. If your angle is obtuse, use the scale with measurements greater than 90°. If it’s an acute angle, make sure you’re looking at the measurements that are less than 90°. Use the scale measurements that are increasing in the direction that your angle is opening up in. If you call, and talk to Jay, tell him Reid and sent you.Follow the other ray up to the measurements on the protractor's arc. ![]() At this point, I'm not affiliated with them, but I'm glad I ran across them. They seem to sell just about everything to do with compasses. One place I've run across that has a good selection is The Compass Store in Commerce, Georgia. Where to Buy a Compassīuy your best compass wherever you find want you want, at a price you want to pay. You'll probably spend somewhere between $25 and $100 for a good compass. Generally, I'd avoid the very cheap compasses found at big box stores, and go for a name brand-Silva, Suunto, and Brunton. This means it is balanced so that it will work fine in both the Northern and Southern Hemispheres. One other thing I like about the Suunto M-3G is that it has a "global" needle. I don't care about miles-it's meters and kilometers for me. The map's UTM grid measures kilometers, not miles. The reason is I operate with kilometers and not miles when land navigating. Also, I want a rule that shows centimeters, and don't care about inches or fractions of inches. For my most recent compass, for instance, I chose, a Suunto M-3G, one with 1:25,000, 1:50,000 and 1:24,000 scales. When choosing the best compass for you, consider the scales you'll need. If I lived in the Rocky Mountains, I could probably find a use for it. Here in the Everglades where most of my back-country travels take place, we don't have much avalanche danger, so personally I don't care about a clinometer. Folks in avalanche country might like this. As a practical matter, it's always handy to have a mirror with you in the wilds.Ī magnifying lens in your compass can be hand for reading small details on the map.Ī clinometer on a compass lets you measure the steepness of a slope, or the height of an object. Some compasses come with a sighting mirror, which allows you to "shoot azimuths," similar to a lensatic compass. Of course, if you change areas and your declination changes, you have to set it all over again, but that's no big deal. Some of the pricier compasses have a declination adjustment, which means you can "set it and forget it" when it comes to adjusting for declination. Avoid those unless that's specifically what you want. The compass dial should turn freely, but not too freely.īe sure the dial goes clockwise from 0 to 360 degrees. That means some of the liquid has leaked out. Don't buy a compass with bubbles in the housing. Kjellstrom introduced the sport of orienteering to the USA in 1946.Ĭompasses don't have to be expensive to be good, but do look for a compass with a liquid-filled dial that keeps the needle from bouncing around too much. Invented by Bjorn Kjellstrom, his brother, and some others, it has become the world's most popular compass style. The orienteering, or base plate, compass has the advantage of being a compass and protractor rolled into one. ![]() Be sure to buy one balanced for your hemisphere. Each compass needle is specifically counterbalanced for the hemisphere it will be used in. In the southern hemisphere, it pulls the south end down. In the northern hemisphere, it pulls the needle's north end down. The earth's magnetic pull wants to pull one end of the needle down. ![]() The reason is that a compass has what's called magnetic dip. When buying a Cammenga, they offer you the option of Northern Hemisphere or Southern Hemisphere. If you don't need all-night illumination, then this could be a good option. They are, however, very durable, made in the U.S.A.Ĭammenga also makes a compass for non-military use, just like it's military compass, except it uses phosphorescence for illumination instead of tritium. Cammenga tritium compasses are a bit over a hundred dollars. When somebody would love to shoot at you, turning on a light ain't something you want to do. Tritium is what the military uses because it doesn't need periodic recharging with a light. The military lensatic compass comes with either tritium or phosphorescent illumination for night navigation. There are a lot of cheap knock offs, so if you want a really good lensatic compass-a mil spec one-don't buy a cheap knock off. The lensatic compass is used by those in the U.S. ![]()
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