Definition: A compass, also known as a lighthouse's light, is a device used to navigate by using stars or other sources of luminosity such as a moon, sun, star, or moonstar. It can be a single compass with two fixed points or a pair of fixed points on an adjustable, rotating or floating surface.
The word 'a-compass' is derived from the Latin term "a" which means "to guide". Therefore, a compass is also known as a "guide compass".
A compass's primary function is to provide direction by guiding a line of sight through the night sky. The object that appears at the fixed point on the rotating or floating surface serves as a starting point for the line of sight.
The two fixed points, which are usually located on a rotating or floating surface, determine the angle of the compass needle. These two points can be located anywhere along the compass's surface, but they are often located near the center of the compass, in the position known as "the north pole". The angle at these fixed points is called the magnetic declination.
The rotation and movement of the compass needle determines its direction. If it is moving clockwise, it points towards the north, while if it's moving counterclockwise, it points away from the north (clockwise).
A compass can also be used to determine the bearing or direction of a line of sight, which is determined by the angle of the compass needle relative to the magnetic declination.
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