ALTITUDE

(Lat. alt us, high, altitudo, height.) In Astronomy, denotes the angle of elevation of a celestial object, or the angle of the visual ray with the horizon. The altitude of a star is apparent or true. The apparent altitude is the angle ascertained immediately from observation; the true altitude is found by correcting the apparent altitude for refraction, parallax, . Altitude is frequently used in Elementary Geometry instead of height. The altitude of a triangle is measured by a straight line drawn from the vertex perpendicular to the base; and the altitude of a cone by the straight line drawn from the vertex perpendicular to the plane of the base. [s. 50]