What kind of compass should I buy?

Since I've started collecting compasses, people I know have assumed that I'm some kind of compass expert (I'm not) and begun asking me what kind of compass to buy. Well, in response, I've put up this page to address that question.

The short answer is: Whatever kind you want to.

The long answer is: whatever meets your needs. For some people this will mean a compass that has most features listed below. For others, it may mean a separate compass for a particular activity. Some of the requirements of different activities overlap with each other, so bear with me.

If you are going to be using the compass with a topographic map, then you will want to make sure it has adjustable declination, a long baseplate or straightedge, and a clear capsule to assist in orienting the compass to the map.

If you're going to be using the compass during orientering, then you will probably not care about declination, as orientering maps are set up for magnetic north.

If you are going to be using the compass along with a GPS (during geocaching, for example) you will almost certainly want a declination adjustment, as most GPSr units report direction in "true" format as opposed to "magnetic". Some GPSr units will allow you to select between "true" and "magnetic".

If you are going to be using the compass without a map then you may not care about declination at all.

Picking a compass

Make sure the compass you choose is going to meet the needs of your activity. Be sure the quality of the compass is sufficient to provide accurate readings. One thing to look for on inexpensive models is how tight the capsule is in the housing. I've seen cheap compasses with so much slop in the capsule that it is possible to alter a bearing by 5 degrees.

Compasses can be broadly divided into the following categories. Note that some models combine features from more than one category.

Baseplate

These compasses have a clear plastic base with at least one straight edge. Most have one or more scales printed on the base. These compasses are generally the least expensive and are suitable for most recreational activities. Many baseplate compasses can be adjusted for declination. Expect to spend at least $10 for a quality baseplate compass with adjustable declination.

Mirrored

The compass is read through a mirror while sighting on a landmark. Many mirrored compasses have adjustable declination. Many modern mirrored compasses (such as most in the Silva line) are also baseplate compasses.

Lensatic

Lensatic compasses generally have a rotating card instead of a needle. You shoot a bearing by aligning a slot in an adjustable lens arm with a guide wire or vane in the lid of the compass, and then read the bearing by looking through the lens at an indicator point. There is generally no provision for declination adjustment. The U.S. "military style" folding pocket compasses are lensatic.

Prismatic

A 'prismatic' compass is similar in function to a lensatic compass, but instead of looking through a lens to read a bearing, you look through a prism. These are generally easier to read than lensatics, in my opinion, and are easier to obtain an accurate bearing.

Direct sighting

In this type of compass you look at the edge of the compass through a lens, and you see a magnified view of the markings on the compass edge. This type of compass is *very* easy to use.

Other

 There are many other compasses which don't fit into these categories. Floating bubble compasses used in cars and boats, novelty compasses, specialized orienteering thumb-compasses, etc.

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