A Brunton® Compass is a type of compass manufactured by the Brunton® company, located in Wyoming. The Brunton® name has such a powerful reputation that generic compasses in a similar design are often referred to as Bruntons even though Brunton® is actually a trademarked name reserved for use on products made by the namesake company. Many suppliers of compasses and supplies for outdoor enthusiasts and geologists stock a range of Brunton® compasses. While they tend to be costly, some people think that they are worth the extra expense.
This compass design was developed in the late 19th century by a Canadian engineer, D. W. Brunton. It includes a compass in a small case with a mirror which allows people to take sightings. The Brunton® compass design also has an inclinometer, also known as a clinometer, which allows people to take angle measurements in addition to sighting the direction they are facing. The design is small enough to fit easily in a field kit, and Brunton® makes some simpler compass designs which can attach to keychains or backpacks for quick sightings.
The design of the Brunton® compass is very precise. Also known as the Brunton® Pocket Transit, the device has been calibrated and designed so that the needle stabilizes quickly when someone opens the compass to take a sighting, and so that the reading is highly accurate. The device also includes a fitting which can be adjusted for the declination, the difference between true north and magnetic north.
When purchasing a Brunton® compass, people have the option of choosing between an azimuth or quad reading style. Azimuth compasses are surrounded with markers which add up to 360 degrees, while quad compasses break up readings into four sets of degree measurements. The style preferred depends on the kind of work someone does, the software someone works with, and the preferences of supervisors or instructors. It's also possible to convert between the two reading styles in the event that someone has the wrong type of compass on hand.
Like other scientific instruments, the Brunton® compass requires some special care. While the design is famous for being very durable, it can be damaged by impact, moisture, and other problems. Keeping the compass in a protective case, protecting it from water, and being careful to use it in environments where magnetic interference is minimal are important for people who want accurate readings. Failure to care for the device properly may lead to erroneous readings, which can be frustrating and sometimes even dangerous.