Difference between revisions of "Constellation"
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| − | In {{Wiki|modern}} {{Wiki|astronomy}}, a [[constellation]] is an internationally defined area of the [[celestial sphere]]. These areas are grouped around asterisms (which themselves are generally referred to in non-technical [[language]] as "[[constellations]]"), which are patterns formed by prominent stars within apparent proximity to one another on [[Earth]]'s night sky. | + | In {{Wiki|modern}} {{Wiki|astronomy}}, a [[constellation]] is an internationally defined area of the [[celestial sphere]]. These areas are grouped around asterisms (which themselves are generally referred to in non-technical [[language]] as "[[constellations]]"), which are patterns formed by prominent {{Wiki|stars}} within apparent proximity to one another on [[Earth]]'s night sky. |
There are also numerous historical [[constellations]] not [[recognized]] by the IAU or [[constellations]] [[recognized]] in regional [[traditions]] of {{Wiki|astronomy}} or [[astrology]], such as {{Wiki|Chinese}}, [[Hindu]] and [[Australian]] Aboriginal. | There are also numerous historical [[constellations]] not [[recognized]] by the IAU or [[constellations]] [[recognized]] in regional [[traditions]] of {{Wiki|astronomy}} or [[astrology]], such as {{Wiki|Chinese}}, [[Hindu]] and [[Australian]] Aboriginal. | ||
| − | The Late Latin term constellātiō can be translated as "set with stars". The term was first used in [[astrology]], of asterisms that supposedly exerted [[influence]], attested in Ammianus (4th century). In English the term was used from the 14th century, also in [[astrology]], of conjunctions of | + | The Late {{Wiki|Latin}} term constellātiō can be translated as "set with {{Wiki|stars}}". The term was first used in [[astrology]], of asterisms that supposedly exerted [[influence]], attested in Ammianus (4th century). In English the term was used from the 14th century, also in [[astrology]], of conjunctions of {{Wiki|planets}}. The {{Wiki|modern}} astronomical [[sense]] of "area of the [[celestial sphere]] around a specific asterism" dates to the mid 16th century. |
| − | Colloquial usage does not distinguish the [[senses]] of "asterism" and "area surrounding an asterism". The {{Wiki|modern}} system of [[constellations]] used in {{Wiki|astronomy}} focuses primarily on [[constellations]] as grid-like segments of the [[celestial sphere]] rather than as patterns, while the term for a star-pattern is asterism. For example, the asterism known as the Big Dipper corresponds to the seven brightest stars of the larger IAU [[constellation]] of {{Wiki|Ursa Major}}. | + | Colloquial usage does not distinguish the [[senses]] of "asterism" and "area surrounding an asterism". The {{Wiki|modern}} system of [[constellations]] used in {{Wiki|astronomy}} focuses primarily on [[constellations]] as grid-like segments of the [[celestial sphere]] rather than as patterns, while the term for a star-pattern is asterism. For example, the asterism known as the Big Dipper corresponds to the seven brightest {{Wiki|stars}} of the larger IAU [[constellation]] of {{Wiki|Ursa Major}}. |
| − | The term circumpolar [[constellation]] is used for any [[constellation]] that, from a particular latitude on [[Earth]], never sets below the horizon. From the {{Wiki|north}} pole, all [[constellations]] {{Wiki|north}} of the [[celestial]] equator are circumpolar [[constellations]]. In the northern latitudes, the informal term equatorial [[constellation]] has sometimes been used for [[constellations]] that lie to the {{Wiki|south}} of the circumpolar [[constellations]]. Depending on the definition, equatorial [[constellations]] can include those that lie entirely between declinations 45° {{Wiki|north}} and 45° {{Wiki|south}}, or those that pass overhead between the tropics of | + | The term circumpolar [[constellation]] is used for any [[constellation]] that, from a particular latitude on [[Earth]], never sets below the horizon. From the {{Wiki|north}} pole, all [[constellations]] {{Wiki|north}} of the [[celestial]] equator are circumpolar [[constellations]]. In the northern latitudes, the informal term equatorial [[constellation]] has sometimes been used for [[constellations]] that lie to the {{Wiki|south}} of the circumpolar [[constellations]]. Depending on the [[definition]], equatorial [[constellations]] can include those that lie entirely between declinations 45° {{Wiki|north}} and 45° {{Wiki|south}}, or those that pass overhead between the tropics of {{Wiki|Cancer}} and [[Capricorn]]. They generally include all [[constellations]] that intersect the [[celestial]] equator. |
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[[Category:Astrology]] | [[Category:Astrology]] | ||
Latest revision as of 03:01, 22 September 2015
In modern astronomy, a constellation is an internationally defined area of the celestial sphere. These areas are grouped around asterisms (which themselves are generally referred to in non-technical language as "constellations"), which are patterns formed by prominent stars within apparent proximity to one another on Earth's night sky.
There are also numerous historical constellations not recognized by the IAU or constellations recognized in regional traditions of astronomy or astrology, such as Chinese, Hindu and Australian Aboriginal.
The Late Latin term constellātiō can be translated as "set with stars". The term was first used in astrology, of asterisms that supposedly exerted influence, attested in Ammianus (4th century). In English the term was used from the 14th century, also in astrology, of conjunctions of planets. The modern astronomical sense of "area of the celestial sphere around a specific asterism" dates to the mid 16th century.
Colloquial usage does not distinguish the senses of "asterism" and "area surrounding an asterism". The modern system of constellations used in astronomy focuses primarily on constellations as grid-like segments of the celestial sphere rather than as patterns, while the term for a star-pattern is asterism. For example, the asterism known as the Big Dipper corresponds to the seven brightest stars of the larger IAU constellation of Ursa Major.
The term circumpolar constellation is used for any constellation that, from a particular latitude on Earth, never sets below the horizon. From the north pole, all constellations north of the celestial equator are circumpolar constellations. In the northern latitudes, the informal term equatorial constellation has sometimes been used for constellations that lie to the south of the circumpolar constellations. Depending on the definition, equatorial constellations can include those that lie entirely between declinations 45° north and 45° south, or those that pass overhead between the tropics of Cancer and Capricorn. They generally include all constellations that intersect the celestial equator.
