ANOMALY, in astronomy, is a technical term used in describing the position of a planet in its orbit. The true anomaly is the angle between the radii drawn from the sun to the planet and to the perihelion point—or the angle turned through by the line joining sun and planet since the planet was last in perihelion. The mean anomaly is the angle which this line would have turned through in the time if the turning had been at a uniform rate corresponding to the period of revolution of the planet. The eccentric anomaly is the same as the eccentric angle defined in elementary conics.