occults

An occultation is an event that occurs when one object is hidden by another object that passes between it and the observer. The word is used in astronomy (see below) and can also be used in a general (non-astronomical) sense to describe when an object in the foreground occults (covers up) objects in the background. In the general sense, occultation applies to the visual scene from low-flying aircraft and in Computer-Generated Imagery (CGI) technology, where foreground objects obscure distant ones in a dynamic way as the scene changes.

Astronomical events which cause occultation include transits and eclipses. The word transit refers to cases where the nearer object appears smaller in apparent size than the more distant object, such as transit of Mercury or Venus across the Sun's disk. The word eclipse generally refers to those instances in which one object moves into the shadow of another. Each of these three events is the visible effect of a syzygy.