Choosing and buying a compass
This can be complicated for someone new to the world of navigation and there are many options on the market. It is important to choose a good compass as one with poor readings could get you into trouble and an accurate compass can save your life. The weather, especially in the mountains, can be quite volatile and, from one minute to the next, visibility can be affected leaving you with only your compass to find your way home.
There are many brands of compasses available, but, to help with your search, we will examine the fundamental qualities that the compass should have.
Components of a compass
There are different models of compasses for different sports. There is the classic pocket watch style, the protractor compass (which is extremely handy for using on a topographic map) and even smaller compasses to attach to your thumb for activities.
Base plate
A good thing to have for your compass, especially if you are going to be using it for orienteering, is a clear base plate. This enables you to place it on the map and still be able to read it. Having a long base plate will also allow you to plot more accurately and a printed scale along the side is also extremely useful.
Mirror
Another type of compass is one with a sighting mirror: this is a handy feature to have as it allows you to take better readings without having to look into the distance and down at the needle at the same time. It has a flip up mirror that permits you to see the arrow and the object in the distance that you are focusing on. The mirror can also be used as a signal in case of emergency! These are of the most accurate compasses.
Declination adjustment
Another good feature to look for is a declination adjustment option: There is something interesting about north and that is that there is a difference between the magnetic north and true north. This is due to the iron content of the Earth and it causes a shift in declination depending on where you are and the time of year - which can be up to 30%. Maps are usually written according to true north or grid north, which means that if you are in an area which affects your declination, you will have to factor that in, or you can have a compass which does so for you automatically. Of course, it is a good idea to be able to do the calculations mentally, and many compasses do come without the option, but if you want the option to have it calculated automatically, invest in one with this feature. You will have to adjust the declination setting depending where you are but the compass will do the rest and have your needle pointing to the true north of the map.
Needle
Needle dip correction is good to watch out for depending on where you are going to be doing your activty. The Earth's magnetic field also has another effect on the needle which is that needle is pulled upwards or downwards depending on the hemisphere. The closer you get to the North Pole, the more the needle is compelled to move downwards and in the South Hemisphere the opposite takes place. The solution for this is to buy a compass designed for the part of the world where you will be navigating. Compass manufacturers have appointed 5 different magnetic areas and compasses are made for each area, or you can invest in a compass that is equipped to work all over the world (which does come with a steeper price, but if you are going to be travelling a lot, it may be worth it instead of investing in more than one). The only way to check is to see if the needle is touching any part of the compass shell as that is a sign that the compass is affected by the magnetic field.
Bezel
A rotating bezel (which is the ring around the circumference of the compass) which should either be marked with 360 degrees and/or have N, E, S and W indications. Having the degrees makes your navigation more precise and the smaller the graduation, the better. Two degrees is ideal.
Other points
The time that the needle takes to settle should be something to look out for as well. The needle should be ideally liquid-filled which will help damper its movement and find north quicker. It is also a good idea to have the direction-of-travel arrows and orienteering lines engraved on the face of the compass so that they do not wear off with use and time.
Buying your compass online is not a bad idea but make sure you do your research prior to purchasing. Compasses are vital for navigation but don't forget that knowing how to use them correctly is essential as well! Make sure to be confident and competent before heading out!
