The elevation of any of the heavenly bodies above the plane of the horizon, or its angular distance from the horizon, measured in the direction of a great circle passing through the zenith. Also the third dimension of a body, considered with regard to its elevation above the ground.
♦ Apparent altitude is that which appears by sensible observations made on the surface of the globe.
♦ Altitude of the pole.
The arc of the meridian between the pole of the heavens and the horizon of any place, and therefore equal to its geographical latitude.
♦ Altitude of the cone of the earth's and moon's shadow, is the height of the one or the other during an eclipse, and is measured from the centre of the body.
♦ Altitude of a shot or shell. The perpendicular height of the vertex of the curve in which it moves above the horizon.
♦ Meridian altitude. The arc of the meridian, or greater or less altitude, measured from the horizon, of a celestial object in its passage over the meridian, above or below the pole, of the place of the observer. In Polar regions two such transits of the sun, and in England similarly, circumpolar stars afford double observations for the determination of time or latitude. The general term is understood by seamen to denote mid-day, when the passage and meridian altitude of the sun affords the latitude.
♦ True altitude is that produced by correcting the apparent one for parallax and refraction.