L occultare frequent.
Occultations occur when one celestial object passes in front of another celestial object. For example, when the Moon passes in front of a background star, light from the background star is prevented from reaching the Earth. A shadow of the Moon is cast by the star onto the Earth, and this shadow sweeps across the Earth at roughly the same speed as the Moon is moving. A special case of an occultation is a Total Solar Eclipse , in which the Moon passes in front of the Sun, obscuring it from view. Many important discoveries have been made in this way.