How to Use a Sighting Compass
A sighting compass, also known as a hand compass, allows the user to view their target and take a bearing at the same time by using a mirror or lens to display the position of the dial. There are two types in use: the lensatic compass and the mirror compass.
Both are relatively simple to use but require practice before fully accurate bearings can be made.
Open the front cover of the compass so it is standing up at 90 degrees from the compass wheel. Position the rear lens so it is leaning slightly forward over the compass wheel.
Locate the landmark of your choice and view it through the compass sights. It may be easier to do this if you raise the compass up to your cheek. Ensure the sighting slot on the rear lens is aligned with the sighting wire on the front sight, and that the wire is in the centre of the chosen landmark.
Read the compass bearing by looking down through the lens on the rear sight and making a note of the position of the lubber line -- the fixed mark on the compass dial that always points in the direction of travel, and from which bearings are taken. You can then travel on this bearing and know that you will reach the landmark, even if you lose sight of it.
Open the cover of the compass and position it so the reflection of the dial is clearly visible in the mirror.
Align the compass so the sighting notch or hole is aimed at the target. Adjust the compass so the sighting line in the mirror is passing directly through the centre of the compass wheel.
Rotate the compass dial until the red part of the needle is sitting inside the red orientating arrow printed on the dial. You can then read the bearing of your target by taking note of the position of the lubber line.