A Magnetic Compass consists of a magnetized needle mounted on a pivot, usually sealed in a small liquid filled case. The needle indicates direction of local magnetic north, if the world has magnetic poles. Most habitable worlds have magnetic fields to deflect solar radiation. May be influenced and give false readings in the vicinity of large masses of iron. Sophisticated models (Cr100) may be used for coarse surveying or navigation tasks.
Compasses are usually tailored to the needs of a specific world since alignment of magnetic pole with geographical pole varies with each world.