The backcountry navigator has many options when it comes to buying a compass. The bad news: many of these are inappropriate for wilderness use. The good news: a handful of them are terrific, and one in particular has dropped dramatically in price.
Direct from the Mazamas lead navigation instructor, here’s the scoop on what to buy and what to avoid. The most important feature of a good compass is adjustable declination! Tip: If a product description says “fixed declination scale”, avoid it.
Desirable features of a good land navigation compass include:
- adjustable declination (the most important feature! Did I mention this?)
- a long straight edge for plotting lines on the map
- meridian lines inside the compass bezel
- a clear base plate, so you can see the map through it
- ruler(s) engraved on one or more of the edges, for measuring map distances
Higher end compasses may have the following (optional) whistles and bells:
- a clinometer, for measuring slope angle, especially good for backcountry skiers
- a sighting mirror, which marginally improves accuracy of bearings
- liquid filled housing, to dampen the compass needle
As you might imagine, compasses not suitable for backcountry use have few or none of these features. Compasses are unsuitable for mountaineering if they:
- are too small for accurate bearings
- do not have meridian lines
- are numbered in 5 degree (or more) increments
- do not have degrees marked from 0 to 360
- have non-transparent housings
- cannot be used for measuring and plotting bearings on a map
Here are three compasses that the Mazamas navi-geeks recommend for wilderness navigation. Students in any Mazamas class with a navigation component are highly encouraged to buy one of these three. All are sold at REI. They are listed in general order of price and features.
1) El Cheapo but it works: Suunto M-2D
This compass has adjustable declination, some bare-bones features and not much else. If you want a compass to keep in the bottom of your pack and don’t plan on using it very often (let’s be honest, that describes most of us!), this would be a good choice. Cost: $24 at REI
2) Just Right: Suunto M3
This is been my go-to compass for many years, and I love it for lots of reasons. A unique feature of this compass is its ergonomic design. Having a curve on one end reminds the user that that’s the end that belongs in your hand. This almost eliminates the common problem of holding the compass backwards, which results in an error of 180°. It does not have a clinometer or sighting mirror, but these are two features that I feel are largely unnecessary for the majority of backcountry users. This compass will best serve the needs of most Mazamas. Cost: $34 at REI
3) High End with special sauce: Brunton 15TDCL
This compass has recently seen a dramatic drop in price and can actually be found at Amazon (as of January 2012) for a rather unbelievable $31. It has a clinometer, liquid housing and sighting mirror. Normally, compasses with all these features sell for well over $50. If you’re a backcountry skier, search and rescue team member, or frequent user of a compass and require extremely accurate bearings, this is probably the one for you. Cost: $42 at REI, $31 at Amazon. (Heck, now that it’s cheaper than my favorite Suunto M3, I may have to get one myself!)
Here are some photos and brief descriptions of compasses that are not suitable for Mazamas classes. If you have one of these, consider getting one of the ones recommended above. You’ll be happy that you did.
Lensatic compass – accurate bearings, but no baseplate
Baseplate compass, but without adjustable declination
Baseplate compass with mirror, but without clear baseplate
Some material on this page is from The Mountaineers