The Probert Encyclopaedia of Science & Technology

OCCULTATION

In astronomy, occultation is the temporary obscuring of a star by a body in the solar system.
Occultations are used to provide information about changes in an orbit, and the structure of objects in space, such as radio sources. The exact shapes and sizes of planets and asteroids can be found when they occult stars. The rings of Uranus were discovered when that planet occulted a star in 1977.
Research Occultation