APPARENT

A term used in Astronomy to denote things as they appear to the eye, in distinction to what they really are. Thus, the apparent altitude of a star denotes the angle which its line of vision makes with the horizon; but the real altitude is found by making a correction for the effects of parallax, which causes the star to appear a little higher than it would if there were no atmosphere. The apparent diameter of a planet is measured by the angle made by two straight lines drawn from the eye to opposite points of its disk; the real diameter is a straight line joining those points; while astronomers call the angle under which the diameter would be seen from the centre of the earth, the true diameter. The apparent or sensible horizon denotes the plane which is a tangent to the earth's surface at the place of the observer; the true horizon is a plane parallel to the former, and pa ing through the centre of the earth. Apparent motion is the vilocityand direction in which a body appears to move to;i < observer who is himself in motion. For example: the arent diurnal motion of the stars from east to west 67 APPORTIONMENT, arises from the rotatory motion of the earth, which carrle* us along with it in an opposite direction. Apparent time is the same as true time, or the hour indicated by the sun's pa age over a meridian; while mean time is that which would be indicated by the sun if its angular velocity in its orbit were uniform. [s. 80]