Editing Constellation (section)

{{short description|Group of stars on the celestial sphere}}
{{About|the star grouping}}
{{Use dmy dates|date=January 2021}}
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| image1            = Orion constellation - Prodromus astronomiae 1690 (5590584).jpg
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Four views of the constellation [[Orion (constellation)|Orion]]: 
* Top: Baroque drawing of Orion from [[Johannes Hevelius]]{{'}} star atlas [[Prodromus_Astronomiae#Firmamentum_Sobiescianum|''Firmamentum Sobiescianum'']], showing the stars as they would appear to an observer looking down upon the imaginary celestial sphere from the outside (left); and illustration from the medieval Persian astronomical text [[Book of Fixed Stars]] (right)
* Bottom: Contemporary map of Orion from the [[International Astronomical Union|IAU]] (left); and photograph of the night sky with drawn lines (right)
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A '''constellation''' is an area on the [[celestial sphere]] in which a group of visible [[star]]s forms [[Asterism (astronomy)|a perceived pattern]] or outline, typically representing an animal, mythological subject, or inanimate object.<ref name="oxforddic2">{{cite web |title=Definition of constellation |url=http://www.oxforddictionaries.com/definition/english/constellation |archive-url=https://web.archive.org/web/20130102014231/http://oxforddictionaries.com/definition/english/constellation |url-status=dead |archive-date=2 January 2013 |access-date=2 August 2016 |work=[[Oxford English Dictionary]]}}</ref>

The first constellations were likely defined in [[prehistory]]. People used them to relate stories of their beliefs, experiences, [[creation myth|creation]], and [[mythology]]. Different cultures and countries invented their own constellations, some of which lasted into the early 20th century before today's constellations were internationally recognized. The recognition of constellations has changed significantly over time. Many changed in size or shape. Some became popular, only to drop into obscurity. Some were limited to a single culture or nation. Naming constellations also helped astronomers and navigators identify stars more easily.<ref name="britannica1">{{cite web | url=https://www.britannica.com/science/constellation | title=Constellation &#124; Definition, Origin, History, & Facts &#124; Britannica | date=5 March 2024 }}</ref>

Twelve (or thirteen) ancient constellations belong to the [[zodiac]] (straddling the [[ecliptic]], which the [[Sun]], [[Moon]], and [[planet]]s all traverse). The origins of the zodiac remain historically uncertain; its [[astrology|astrological]] divisions became prominent {{circa|400 BC}} in [[Babylonian astronomy|Babylonian]] or [[Chaldea]]n astronomy.<ref>{{cite journal |last=Britton |first=John P. |date=2010 |title=Studies in Babylonian lunar theory: part III. The introduction of the uniform zodiac |journal=Archive for History of Exact Sciences |volume=64 |issue=6 |pages=617–63 |jstor=41134332 |doi=10.1007/S00407-010-0064-Z |s2cid=122004678 |quote=[T]he zodiac was introduced between −408 and −397 and probably within a very few years of −400.}}</ref> Constellations appear in Western culture via Greece and are mentioned in the works of [[Hesiod]], [[Eudoxus of Cnidus|Eudoxus]] and [[Aratus]]. The traditional 48 constellations, consisting of the zodiac and 36 more (now 38, following the division of [[Argo Navis]] into three constellations) are listed by [[Ptolemy]], a Greco-Roman astronomer from [[Alexandria]], Egypt, in his ''[[Almagest]]''. The formation of constellations was the subject of extensive [[mythology]], most notably in the ''[[Metamorphoses (Ovid)|Metamorphoses]]'' of the Latin poet [[Ovid]]. Constellations in the far [[southern celestial hemisphere|southern sky]] were added from the 15th century until the mid-18th century when European explorers began traveling to the [[Southern Hemisphere]]. Due to Roman and European transmission, each constellation has a Latin name.

In 1922, the [[International Astronomical Union]] (IAU) formally accepted the modern list of [[IAU designated constellations|88&nbsp;constellations]], and in 1928 adopted official constellation boundaries that together cover the entire celestial sphere.<ref name="IAU1928">{{cite book |first=Eugène |last=Delporte |publisher=[[International Astronomical Union]] |title=Délimitation scientifique des constellations |url=https://books.google.com/books?id=v3XvAAAAMAAJ |year=1930}}</ref><ref name="auto">{{cite web |title=Star Tales: The final 88 |first=Ian |last=Ridpath |year=2018|url=http://www.ianridpath.com/startales/startales1d.html#delporte}}</ref> Any given point in a [[celestial coordinate system]] lies in one of the modern constellations. Some [[stellar designation|astronomical naming systems]] include the constellation where a given celestial object is found to convey its approximate location in the sky. The [[Flamsteed designation]] of a star, for example, consists of a number and the genitive form of the constellation's name.

Other star patterns or groups called [[asterism (astronomy)|asterisms]] are not constellations under the formal definition, but are also used by observers to navigate the night sky. Asterisms may be several stars within a constellation, or they may share stars with more than one constellation. Examples of asterisms include the teapot within the constellation [[Sagittarius (constellation)|Sagittarius]], or the [[big dipper]] in the constellation of [[Ursa Major (constellation)|Ursa Major]].<ref name="DOCdb2018">{{cite web|url=http://www.docdb.net/show_object.php?id=saucepan|title=DOCdb Deep Sky Observer's Companion – the online database|access-date=21 September 2018}}</ref><ref name="SoftBisque2018">{{cite web|title=A Complete List of Asterisms|url=https://www.bisque.com/tom/asterisms/list.asp|access-date=21 September 2018|archive-date=29 September 2012|archive-url=https://web.archive.org/web/20120929040705/http://www.bisque.com/tom/asterisms/list.asp|url-status=dead}}</ref>