Editing Crux (section)

==Visibility==
[[File:Deep Crux wide field with fog.jpg|right|thumb|upright=1.2|Deep exposure of Crux, [[Coalsack Nebula]], and [[IC 2944]]]]
Crux is easily visible from the [[southern hemisphere]], south of 35th parallel at practically any time of year as circumpolar. It is also visible near the horizon from [[Tropics|tropical latitudes]] of the [[northern hemisphere]] for a few hours every night during the northern winter and spring. For instance, it is visible from [[Cancun]] or any other place at latitude 25° N or less at around 10 pm at the end of April.<ref>{{cite book | title=Field Guide to the Stars and Planets | author=Pasachoff, Jay M | year=2000 | publisher=Houghton Mifflin | isbn=978-0-395-93431-9 | page=67}}</ref><ref name=tirionconst/> There are 5 main stars.
Due to [[precession]], Crux will move closer to the South Pole in the next millennia, up to 67 degrees south declination for the middle of the constellation. However, by the year 14,000, Crux will be visible for most parts of Europe and the continental United States. Its visibility will extend to North Europe by the year 18,000 when it will be less than 30 degrees south declination.

===Use in navigation===
[[Image:Pole01-eng.svg|thumb|right|upright=1.2|Locating the south celestial pole]]
In the [[Southern Hemisphere]], the Southern Cross is frequently used for [[Celestial Navigation|navigation]] in much the same way that [[Polaris]] is used in the [[Northern Hemisphere]]. Projecting a line from [[Gacrux|γ]] to [[Acrux|α Crucis]] (the foot of the crucifix) approximately {{frac|4|1|2}} times beyond gives a point close to the Southern Celestial Pole{{sfn|Ridpath|Tirion|2017|pp=134–135}} which is also, coincidentally, where it intersects a perpendicular line taken southwards from the east–west axis of [[Alpha Centauri]] to [[Beta Centauri]], which are stars at an alike declination to Crux and of a similar width as the cross, but higher magnitude.<ref name= Grainger>{{cite book |title = Don't die in the Bundu| first1 = DH| last1 = Grainger| year = 1969| location = Cape Town| isbn = 0-86978-056-5| pages = 84–86| edition = 8th}}</ref>  [[Argentina|Argentine]] [[gaucho]]s are documented as using Crux for night orientation in the [[Pampa]]s and [[Patagonia]].

Alpha and Beta Centauri are of similar declinations (thus distance from the pole) and are often referred as the "Southern Pointers" or just "The Pointers", allowing people to easily identify the Southern Cross, the constellation of Crux.  Very few bright stars lie between Crux and the pole itself, although the constellation [[Musca]] is fairly easily recognised immediately south of Crux.<ref name= Grainger/>

===Bright stars===
Down to apparent magnitude +2.5 are 92 stars [[list of brightest stars|that shine the brightest as viewed from the Earth]]. Three of these stars are in Crux making it the most densely populated as to those stars (this being 3.26% of these 92 stars, and in turn being 19.2 times more than the expected 0.17% that would result on a homogenous distribution of all bright stars and a randomised drawing of all 88 constellations, given its area, 0.17% of the sky).