Editing Cygnus (constellation) (section)

{{Short description|Constellation in the northern celestial hemisphere}}
{{Use dmy dates|date=September 2021}}
{{Infobox constellation
| name = Cygnus
| abbreviation = Cyg
| genitive = Cygni
| pronounce = {{IPAc-en|ˈ|s|ɪ|ɡ|n|ə|s}}, genitive {{IPAc-en|ˈ|s|ɪ|ɡ|n|aɪ}}
| symbolism = the [[Swan]] or [[Northern Cross (asterism)|Northern Cross]]
| RA = {{RA|20.62}}
| dec= {{DEC|+42.03}}
| family = [[Hercules Family|Hercules]]
| quadrant = NQ4
| areatotal = 804
| arearank = 16th
| numbermainstars = 9
| numberbfstars = 84
| numberstarsplanets = 97
| numberbrightstars = 4
| numbernearbystars = 1
| brighteststarname = [[Deneb]] (α Cyg)
| starmagnitude = 1.25
| neareststarname = [[61 Cygni|61 Cyg]]
| stardistancely = 11.36
| stardistancepc = 3.48
| numbermessierobjects = 2
| meteorshowers = [[October Cygnids]]<br />[[Kappa Cygnids]]
| bordering = [[Cepheus (constellation)|Cepheus]]<br />[[Draco (constellation)|Draco]]<br />[[Lyra]]<br />[[Vulpecula]]<br />[[Pegasus (constellation)|Pegasus]]<br />[[Lacerta]]
| latmax = [[North Pole|90]]
| latmin = [[40th parallel south|40]]
| month = September
| notes=}}
'''Cygnus''' is a northern [[constellation]] on the plane of the [[Milky Way]], deriving its name from the [[Latinisation of names|Latinized]] [[Greek language|Greek]] word for [[swan]].<ref name="Starwatch"/> Cygnus is one of the most recognizable constellations of the northern summer and autumn, and it features a prominent [[asterism (astronomy)|asterism]] known as the [[Northern Cross (asterism)|Northern Cross]] (in contrast to the [[Southern Cross]]). Cygnus was among the 48 constellations listed by the 2nd century astronomer [[Ptolemy]], and it remains one of the 88 modern constellations.

Cygnus contains [[Deneb]] (ذنب, translit. ''ḏanab,'' tail){{snd}}one of the [[brightest stars]] in the night sky and the most distant [[first-magnitude star]]{{snd}}as its "tail star" and one corner of the [[Summer Triangle]] the constellation forming an east pointing [[Altitude (triangle)|altitude of the triangle]].<ref name="Starwatch">{{cite web |url=https://www.theguardian.com/science/2018/jul/29/starwatch-the-bright-stars-of-the-summer-triangle |title=Starwatch: the bright stars of the Summer Triangle |author=Stuart Clark |date=29 July 2018 |work=The Guardian}}</ref> It also has some notable X-ray sources and the giant [[stellar association]] of [[Cygnus OB2]].<ref>{{cite web |url=https://scitechdaily.com/star-cluster-cygnus-ob2/ |work=SciTechDaily |title=Star Cluster Cygnus OB2 |author=Chandra X-ray Observatory |date=8 November 2012|author-link=Chandra X-ray Observatory}}</ref>  One of the stars of this association, [[NML Cygni]], is one of the [[List of largest stars|largest stars currently known]]. The constellation is also home to [[Cygnus X-1]], a distant X-ray binary containing a supergiant and unseen massive companion that was the first object widely held to be a [[black hole]].
Many star systems in Cygnus have known planets as a result of the [[Kepler Mission]] observing one patch of the sky, an area around Cygnus.

Most of the east has part of the [[Hercules–Corona Borealis Great Wall]] in the [[deep-sky object|deep sky]], a giant [[galaxy filament]] that is the largest known structure in the observable universe, covering most of the northern sky.