Azimuth circle –
Azimuth circle is a non magnetic metal ring equipped with sighting devices for observing bearings of objects (celestial bodies, terrestrial bodies, targets, vessels, etc). It consists of a graduated ring equipped with a sighting vane on each side, which fits concentrically over a compass/ compass repeater. To ensure that the compass is exactly kept horizontal when taking an observation, generally the azimuth rings are provided with two bubble gauges, which must be aligned properly when taking an observation.
Basically, azimuth and bearing are the same in meaning: the horizontal angle that a line drawn from your position to the object sighted makes with a line drawn from your position to true north. The word azimuth, however, applies only to bearings of heavenly bodies. For example, it is not the bearing, but the azimuth of the Sun; and not the azimuth, but the bearing of a Light house
