#nutation

Model for explaining the very slow motion called precession of the equinoxes. The phenomenon—which sparked scientific and doctrinal controversies—was investigated for several centuries. It was one of the arguments cited by Copernicus in support of his astronomical system. The model, actuated by a series of hand-operated gears, also simulates the nutation of the Earth's axis

Precession: “the slow movement of the axis of a spinning body around another axis due to a torque (such as gravitational influence) acting to change the direction of the first axis. It is seen in the circle slowly traced out by the pole of a spinning gyroscope”

versus

Nutation: “a periodic oscillation of the earth's axis that causes the precession of the poles to follow a wavy rather than a circular path”

Kontranutation – DocCheck Flexikon

Kontranutation – DocCheck Flexikon.