Editing Capricornus (section)

==Notable features==
[[Image:CapricornusCC.jpg|thumb|left|The constellation Capricornus as it can be seen with the naked eye<ref>{{cite web |url=http://www.allthesky.com/constellations/capricornus.html |title=Capricornus, the Goat |series=Constellations – Digital Images of the Sky |publisher=Allthesky.com |access-date=2012-05-16}}</ref>]]

===Stars===
{{See also|List of stars in Capricornus}}
Capricornus is a faint constellation, with only one star above magnitude&nbsp;3; its [[Bayer designation|alpha star]] has a magnitude of only 3.6.

The brightest star in Capricornus is [[Delta Capricorni|δ&nbsp;Capricorni]], also called Deneb Algedi, with a magnitude of 2.9, located 39&nbsp;light-years from Earth. Like several other stars such as [[Denebola]] and [[Deneb]], it is named for the Arabic word for "tail or end" (''deneb'') and “young goat / kid” (al-gedi); its traditional name means "tail to head” or “back to the beginning", which could be related to the Ouroboros or Janus since the zodiac relates to January. Deneb Algedi is a [[Beta Lyrae variable]] star (a type of [[eclipsing binary]]). It ranges by about 0.2&nbsp;magnitudes with a period of 24.5&nbsp;hours.{{sfn|Ridpath|Tirion|2001|pp=102–103}}

The other bright stars in Capricornus range in magnitude from 3.1 to 5.1. [[Alpha Capricorni|α&nbsp;Capricorni]] is a multiple star. The primary ([[Alpha2 Capricorni|α<sup>2</sup>&nbsp;Cap]]), 109&nbsp;light-years from Earth, is a yellow-hued giant star of magnitude&nbsp;3.6; the secondary ([[Alpha1 Capricorni|α<sup>1</sup>&nbsp;Cap]]), 690&nbsp;light-years from Earth, is a yellow-hued supergiant star of magnitude&nbsp;4.3. The two stars are distinguishable by the naked eye, and both are themselves multiple stars. α<sup>1</sup>&nbsp;Capricorni is accompanied by a star of magnitude&nbsp;9.2; α<sup>2</sup>&nbsp;Capricorni is accompanied by a star of magnitude 11.0; this faint star is itself a binary star with two components of magnitude&nbsp;11. Also called Algedi or Giedi, the traditional names of α&nbsp;Capricorni come from the Arabic word for "the kid", which references the constellation's mythology.{{sfn|Ridpath|Tirion|2001|pp=102–103}}

[[Beta Capricorni|β Capricorni]] is a [[double star]] also known as Dabih. It is a yellow-hued giant star of magnitude&nbsp;3.1, 340&nbsp;light-years from Earth. The secondary is a blue-white hued star of magnitude 6.1. The two stars are distinguishable in binoculars. β&nbsp;Capricorni's traditional name comes from the Arabic phrase for "the lucky stars of the slaughterer," a reference to ritual sacrifices performed by ancient Arabs at the [[heliacal rising]] of Capricornus.<ref>{{cite book |first=Mark R. III |last=Chartrand |year=1983 |title=Skyguide: A Field Guide for Amateur Astronomers |page=126 |publisher=Golden Press |isbn=0-307-13667-1}}</ref> Another star visible to the naked eye is [[Gamma Capricorni|γ&nbsp;Capricorni]], sometimes called Nashira ("bringing good tidings"); it is a white-hued giant star of magnitude&nbsp;3.7, 139&nbsp;light-years from Earth. [[Pi Capricorni|π Capricorni]] is a double star with a blue-white hued primary of magnitude&nbsp;5.1 and a white-hued secondary of magnitude&nbsp;8.3. It is 670&nbsp;light-years from Earth and the components are distinguishable in a small telescope.{{sfn|Ridpath|Tirion|2001|pp=102–103}}

===Deep-sky objects===
[[File:Messier_30_Hubble_WikiSky.jpg|thumb|right|The globular cluster Messier 30 imaged by the [[Hubble Space Telescope]]]]
Several galaxies and star clusters are contained within Capricornus. [[Messier 30]] is a globular cluster located 1&nbsp;degree south of the galaxy group that contains [[NGC 7103]]. The constellation also harbors the wide spiral galaxy [[NGC 6907]].

Messier 30 (NGC 7099) is a centrally-condensed globular cluster of magnitude 7.5&nbsp;. At a distance of 30,000&nbsp;light-years, it has chains of stars extending to the north that are resolvable in small amateur telescopes.{{sfn|Ridpath|Tirion|2001|pp=102–103}}

One [[galaxy group]] located in Capricornus is [[HCG 87]], a group of at least three galaxies located 400&nbsp;million [[light-years]] from Earth ([[redshift]] 0.0296). It contains a large [[elliptical galaxy]], a face-on [[spiral galaxy]], and an edge-on spiral galaxy. The face-on spiral galaxy is experiencing abnormally high rates of [[star formation]], indicating that it is [[interacting galaxy|interacting]] with one or both members of the group. Furthermore, the large elliptical galaxy and the edge-on spiral galaxy, both of which have [[active galactic nucleus|active nuclei]], are connected by a stream of stars and dust, indicating that they too are interacting. Astronomers predict that the three galaxies may [[galaxy merger|merge]] millions of years in the future to form a giant elliptical galaxy.<ref name="objects">{{Harvnb|Wilkins|Dunn|2006}}</ref>