azimuth, in astronomy, one coordinate in the altazimuth coordinate system. It is the angular distance of a body measured westward along the celestial horizon from the observer's south point.

Two coordinates describing the position of an object above Earth in a coordinate system called the altazimuth, or horizon, system, and used in astronomy, gunnery, navigation, surveying, and other fields. Altitude in this sense is expressed as angle of elevation (up to 90°) above the horizon. Azimuth, in astronomical measurement, is the number of degrees clockwise from due north to the point on the horizon directly below the object.

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