Once you know how to use a compass, you will always want one with you so you can find your way in case you ever get lost in unfamiliar terrain. Knowing how to read a compass can get you out of your lost situation very quickly. I’m sure you’ll agree that a compass must fit your needs whether it be for hiking or sailing, and should be well made so that it doesn’t fail you when needed. That was our top criteria for selecting the best compass. If you want to find your direction right away, the Eyesky Waterproof Metal Sighting Compass, is a combination of all these features and was selected the “Best Overall” pick from our editorial team.
Compass Buying Guide
What is a Compass?
A compass is used for navigation and aids the user in finding different directions. Depending on the compass, some will show a true north while other models show what is called a magnetic north.
True north and south are based on the rotational axis of the Earth. Magnetic North and South varies a little bit due to the specific magnetic field of your location while you are using it.
There are many different types of compasses available. What you plan on using it for will determine which compass is the best choice for you.
Types of Compasses
There are a large variety of compasses on the market today. We have listed the different types of compasses so you can understand the differences between each one.
- Thumb Compass – This is a basic compass and one of the most popular available. It does not normally have a base plate and is usually transparent. They are compact, small and easy to carry.
Most often these are the compass of choice used for orienteering. They can be attached to your thumb easily and the thumb becomes the base plate.
- Hand Bearing Compass – A small, compact compass with sights is called a hand bearing compass. This style can easily be used with one hand for your convenience. The sight allows the user to see objects in the distance and take a bearing against them. Depending on the model, the sites in these compasses are very basic, with a notch at one end. Sometimes they are more complicated and include mirrored sights or prismatic sights. Foresters and surveyors often use the hand bearing compass because they are so accurate.
- Prismatic Hand Bearing Compass – This type of compass has a closing lid that features a glass window. This compass provides very pinpointed and accurate readings so you always know where you are. Experienced users can take bearings to a fraction of a degree. Prismatic Hand Bearing Compasses are more expensive than other models of compass but if accuracy is super important to you, the way it needs to be in surveying or forestry, you will want to invest the extra money.
- Gyrocompass – This type of compass is used almost exclusively on ships. It is very expensive. This type of compass is not a magnetic compass, it finds true North which is usually 1,000 miles away from magnetic north. They use a fast spinning disc that is battery powered or electrically powered to gain the high speeds. The high speed that is produced creates the gyroscopic effect and that allows the compass to find the accurate true North. gyrocompass can sometimes take up to an hour to reach the high enough speeds to find a bearing.
They are not affected by any ferrous metals like steel because they are not using the magnetic field. The drawback to this type of compass is that it can receive interference if there is a sudden shift in movement, altitude or direction. They can and will adjust themselves but it takes a little bit of time.
Common Errors in Compass Reading
- Mechanical – The first type of compass error is mechanical. The needle might stick a little or it is not perfectly balanced and you’re not holding the compass level which will make the heavy end want to drift down where it scrapes along the bottom of the compass card. It can also point upwards and scrapes along the top of the glass. If the sighting posts have some wobble or are bent, that will affect accuracy.
- Precision – How the compass is marked and aligned with the compass needle is important. It is a common place for error. There are several reasons for errors in precision. If the needle isn’t centered in the card it will be unbalanced. Also the user could be looking at the reading at an angle.
- Magnetic Interference – One of the major sources of compass reading errors is the presence of magnetic fields that are stray or metal that might affect the compass reading. If you have your compass in the same pocket as your cell phone, this could drastically affect it.
- User Errors– The second major source of error externally for the compass is you… or whoever is using the compass. User error is probably the most difficult to fix because it can be something slight like not waiting long enough for the needle to land or something major. Human error is always a possibility so it is important that the user try to ensure that they handle and use the compass as accurately and error free as possible.
Common Features of a Basic Compass
Below are some of the basic features that a basic compass has.
- Magnetized Needle – The end that points to the strongest magnetic field which is typically the magnetic North Pole. The magnetized needle is usually the red end of a pivoting compass needle.
- Liquid Filled Capsule – The dial that has the needle and dampening field is called the liquid filled capsule. The liquid slows the jiggling of the needle and makes it come to a rest faster than an air-filled housing. In extremely cold weather or high elevations, the liquid may create a bubble after it contracts.
- Rotating Bezel – The rotating bezel is marked from 0-360 in 2 degree increments. These numbers are on the outer edge of the compass capsule. The small the interval of degrees the easier it is to take an accurate bearing.
- Bass plate with Ruler – The base plate of a compass is a rectangular base where the compass sits. The higher quality compasses have rulers that are etched into the straight edges of the plate. You want to select a compass that offers scales that you will use. If you want to draw bearings on a map, a long straight edge is very helpful to get this done.
- Orienting Arrow/Parallel meridian lines – This is located on the bottom of the compass housing. The end of the arrow’s directional end is red and paired with the meridian lines helps users to orient the compass to the map.
- Index line or Direction-of-travel line – These are located at one end of the base plate. The point of the compass that you set or read the bearing measurement is the point of the compass dial.
There are several important factors that need to be considered when it comes to a compass. The information contained in this buyer’s guide can help you choose the compass that is right for what you will be using it for. Having the right information makes sorting through all of the different choices much easier. While most compasses all do the same thing, there are different quality levels and that can affect the accuracy they have.
Compasses are a crucial piece of equipment that is beneficial for campers, hikers and other outdoor enthusiasts. They are very valuable to have to prevent getting lost or to know which direction you want to go to reach your destination. The right compass will be one of the most used pieces of equipment you have, especially if you hike a lot.