- Grazing occultation
occultationis an astronomical event that occurs when one celestial object is hidden by another celestial object that passes between it and the observer. A grazing occultation is a special type of lunar occultation that occurs within a mile or two of the edge of an occultation's predicted path, referred to as its northern or southern limit. Within that narrow zone, an observer may see the star intermittently disappearing and reappearing as the irregular limb of the moon moves past the star, creating what is known as a grazing occultation. From an observational and scientific standpoint, these "grazes" are the most dynamic and interesting of lunar occultations.
The accurate timing of lunar occultations is performed regularly by (mostly amateur) astronomers. If several observers with telescopes and timing equipment are positioned at intervals within this zone, they can each time the sequence of disappearances and reappearances as seen from their observing location. If the positions of the observing locations are measured, the timings can be analyzed afterwards to obtain a very accurate fix of the position of the Moon relative to the star and to determine the details of the lunar mountains and valleys seen in profile along the moon's edge.
Such observations are useful for refining knowledge of the positions and motions of stars. Also, the star's disappearances or reappearances may occur in steps, indicating a previously undiscovered close double star that cannot be resolved by direct observations.
Grazing lunar occultation
* Transit (occultations of planets by other planets)
* [http://lunar-occultations.com/iota/iotandx.htm Internationl Occultation Timing Association (IOTA)]
Wikimedia Foundation. 2010.
Look at other dictionaries:
Occultation — See also: Occult (disambiguation) In this July 1997 still frame captured from video, the bright star Aldebaran has just reappeared on the dark limb of the waning crescent moon in this predawn occultation. An occultation is an event that occurs… … Wikipedia
Grazing lunar occultation — A lunar occultation occurs when the Moon, moving along its orbital path, passes in front of a star or other celestial object, as seen by an observer (normally on the Earth). A grazing lunar occultation (also lunar grazing occultation, lunar graze … Wikipedia
90 Antiope — (pronEng|ænˈtaɪəpi an tye ə pee ) is an asteroid discovered on October 1, 1866 by Robert Luther. The 90th asteroid to be discovered, it is named after Antiope from Greek mythology, though it is disputed as to whether this is Antiope the Amazon or … Wikipedia
Baily's beads — As the moon grazes by the Sun during a solar eclipse, the rugged lunar topography allows beads of sunlight to shine through in some places, and not in others. This effect is called Baily s beads , in honour of Francis Baily, who first provided an … Wikipedia
Radio clock — A radio clock is a clock that is synchronized by a time code bit stream transmitted by a radio transmitter connected to a time standard such as an atomic clock. Such a clock may be synchronized to the time sent by a single transmitter, such as… … Wikipedia
Transit of Earth from Saturn — A transit of Earth across the Sun as seen from Saturn takes place when the planet Earth passes directly between the Sun and Saturn, obscuring a small part of the Sun s disc for an observer on Saturn. During a transit, Earth can be seen from… … Wikipedia
Transit of Phobos from Mars — [ right|240px|thumbnail|Phobos transits the Sun, as seen by Mars Rover Opportunity on March 10 2004] A transit of Phobos across the Sun as seen from Mars takes place when Phobos passes directly between the Sun and a point on the surface of Mars,… … Wikipedia
Chronology of Jesus — See also: Gospel harmony, Historical Jesus, and Historicity of Jesus Medieval Russian icon depicting the life of Jesus. The Chronology of Jesus aims to establish a historical order for some of the events of the life of Jesus in the four… … Wikipedia
Asteroid-impact avoidance — Planetary defense redirects here. For defending against alien invasion in fiction, see alien invasion. Artist s impression of a major impact event. The collision between Earth and an asteroid a few kilometres in diameter releases as much energy… … Wikipedia
erasure — Synonyms and related words: abbreviation, ablation, abrasion, abrasive, abridgment, attrition, blackout, blocking, blot, blotting, blotting out, blue penciling, bowdlerization, buffing, burnishing, cancel, cancellation, censoring, censorship,… … Moby Thesaurus