Compass Requirements - photographs and models included -- MUST READ INFO

All compasses have a magnetized needle that points north, and have a way to indicate direction of travel. Mountaineering requires a compass with additional qualities. Compasses that hang from parka zippers or hook on watchbands are not suitable for this course or as part of your ten essentials. Good compasses are easily found, but many compasses on the market are not suitable for use in this course.

Caution - when buying a compass

Every year, some students buy unsuitable compasses, usually the result of not following the guidelines below. Often, a sales person (who may or may not know the requirements of a good compass) was asked for advice. To complicate things further, our local outdoor stores sometimes run out of stock of the recommended compasses. Sales people will try to recommend alternatives (mostly unsuitable). They aren't malicious, but in fact are trying to be helpful. In reality, a good mountaineering compass has no substitute. Retailers will carry a variety of compasses, some suitable, some not.

Required Features

1.	Adjustable declination: A moveable orienting arrow, which provides a built-in declination adjustment. If there is one feature that simplifies map and compass work, this is it. Compasses with adjustable declination can often be identified by the presence of an adjustment screw on the back of the housing (on the underside of the compass, look at the bezel - the screw is usually brass or copper colored).
	•  All students MUST have a compass with adjustable declination. Be aware that REI's compass summary sheet has been incorrect (and may still be), about adjustable declination, particularly on some Brunton compasses. Be very sure to understand these requirements, not merely to read the REI summary sheet. •  If you already have a compass without adjustable declination, you may not use it in this course. Recent experience indicates that such compasses detract from the learning experience.
2.	A transparent rectangular base plate with a direction of travel arrow or a sighting mirror.
	•  Transparency allows map features to be seen underneath the compass. •  The rectangular shape provides straight edges and square angles for plotting and triangulating on the map.
3.	A bezel (the rotating housing) marked clockwise from 0 to 360 degrees in increments of two degrees or less. (Some compasses are numbered backwards, in a counterclockwise direction. These are not suitable for use in this course.) In general, bezels should be large to allow use while wearing gloves - the larger size also improves accuracy. Black bezels with sloping sides are preferred.
4.	Meridian lines: Marks on the bottom of the interior of the circular compass housing, marked with parallel 'meridian lines', which rotate with the bezel when it is turned. The meridian lines run parallel to the north-south axis of the bezel, however turned. Meridian lines are necessary for plotting and triangulating on the map.
5.	A ruler and/or gradient scale engraved on one of the straight edges, used for measuring distances.
6.	A 3 to 4-inch base plate. A longer straight edge makes map work easier.

Diagram of minimum features:

Additional recommendations

•	A sighting mirror in the cover: This reduces errors introduced when moving the compass from eye-level after sighting to waist-level for reading the dial.
•	A liquid-filled housing to reduce erratic needle movement (only needed on some compasses). In some cases, steadying the compass needle can be difficult.
•	An inclinometer: a gravity driven arrow that allows you to measure slope angle.
•	Note: Stay away from "quadrant-type" compasses marked from 0 to 90 degrees, 0 to 90, 0 to 90, 0 to 90, because they are difficult to use.

Diagram of recommendations:

Recommended compasses

Compasses must have the first 6 features listed, including a declination adjustment mechanism. Don’t buy a new compass without this declination adjustment feature. The declination adjustment can usually be identified by the presence of a small adjustment screw on the back of the bezel (on the underside of the compasss).

The following list includes compasses that are equipped with appropriate features. This list is not all-inclusive, but is representative of good quality, fully equipped compasses suitable for this course and for other mountaineering activities. Prices for a good compass start at $20 without a mirror, more with a mirror.

Compasses SUITABLE for the course include:

• SILVA 25 Ranger Pro
• SILVA 15 Ranger
• NEXUS model ProElite 25
• NEXUS Ranger 15
• SUUNTO model M2D Locator (around $20 - a best value for a compass without a mirror)
• SUUNTO M3G
• SUUNTO M2
• SUUNTO M5
• SUUNTO MC1D Professional
• SUUNTO MC2
• SUUNTO MC2 Global

Photographs of acceptable compasses - we suggest you look at this link before buying a compass.

Unacceptable compasses

Compasses are unsuitable for mountaineering if they are too small for accurate bearings, do not have meridian lines, are numbered in 5 degree increments, have non-transparent housings, do not have degrees from 0 to 360, or cannot be used for measuring and plotting bearings on a map.

Features which make a compass undesirable or unsuitable:

• Lack of a straight edge for plotting lines on a map
• Lack of declination adjustment
• Lack of meridian lines inside the bezel
• Small size -- less than 3.5" x 2.2"
• Small bezel - less than 2" in diameter

UNSUITABLE compasses for this course:

• SILVA model Guide Type 26
• NEXUS model Star 7N2
• BRUNTON model 8020 GPS
• BRUNTON model 9020 G

Photographs of unacceptable compasses (many of which are commonly sold at local outdoor retailers) - we suggest you look at this link before buying a compass.