The angle between the periapsis of an orbit and the position of an imaginary body that orbits in the same period as the real one but at a constant angular speed. The angular speed assigned to the imaginary body is the average angular velocity (the mean motion) of the real orbiting body. The angle of mean anomaly is measured from the body being orbited, in the direction of orbital motion. See also Kepler's Equation.
Subjects: Astronomy and Astrophysics.