Results for Crux
On this page:
 
 
(krʊks) [Lat.,=cross], small but brilliant southern constellation whose four most prominent members form a Latin cross, the famous Southern Cross. The long arm of the cross, terminating in the brightest member, Acrux (Alpha Crucis), points almost directly at the south celestial pole. Two other stars, Mimosa (Beta Crucis) and Gacrux (Gamma Crucis) are also among the brightest in the sky. Also in Crux is the Coalsack, a famous dark nebula. Crux reaches its highest point in the evening sky in May; its location in the far southern sky makes it visible most of the year to southern observers but not at all to observers north of about 25°N lat.


 
 
WordNet: Crux
Note: click on a word meaning below to see its connections and related words.

The noun has one meaning:

Meaning #1: a small conspicuous constellation in the southern hemisphere in the Milky Way near Centaurus
  Synonyms: Southern Cross, Crux Australis


 
Wikipedia: Crux
Crux
Crux
Click for larger image
List of stars in Crux
Abbreviation: Cru
Genitive: Crucis
Symbology: Southern Cross
Right ascension: 12.5 h
Declination: −60°
Area: 68 sq. deg. (88th)
Main stars: 4
Bayer/Flamsteed stars: 16
Stars known to have planets: 1
Bright stars: 4
Nearby stars: 0
Brightest star: Acrux (α Cru) (0.87m)
Nearest star: η Cru (64.2 ly)
Messier objects: 0
Meteor showers: Crucids
Bordering constellations: Centaurus

Musca

Visible at latitudes between +20° and −90°
Best visible at 21:00 (9 p.m.) during the month of May

Crux (IPA: /ˈkrʊks/, Latin: cross), commonly known as the Southern Cross (Crux Australis, in contrast to the Northern Cross), is the smallest of the 88 modern constellations, but nevertheless one of the most distinctive. It is surrounded on three sides by the constellation Centaurus while to the south lies the Fly (Musca). Ancient Greeks originally thought Crux was part of Centaurus, but it was defined as a separate asterism in the 16th century after Amerigo Vespucci's expedition to South America in 1501. Vespucci mapped the two stars, Alpha Centauri and Beta Centauri as well as the stars of the Crux. Although these stars were known to the ancient Greeks, gradual precession of the equinoxes had lowered them below the European skyline so that they were forgotten there. For example at the latitude of Athens in 1000 B.C., Crux was clearly visible, although it was low in the sky. [1] However, by 400 A.D., most of the constellation never rose above the horizon for Athenians. [2]

Notable features

With the lack of a significant pole star in the southern sky (Sigma Octantis is closest to the pole, but is too faint to be useful for the purpose), two of the stars of Crux (Alpha and Gamma, Acrux and Gacrux respectively) are commonly used to mark south. Following the line defined by the two stars for approximately 4.5 times the distance between them leads to a point close to the Southern Celestial Pole.

Alternatively, if a line is constructed perpendicularly between Alpha Centauri and Beta Centauri, the point where the above line and this line intersect marks the Southern Celestial Pole. The two stars are often referred to as the "Pointer Stars" or "White Pointers", allowing people to easily find the top of Crux.

Contrary to some people's belief, it is not opposite to Ursa Major. In fact, in tropical regions both Crux (low in the South) and Ursa Major (low in the North) can be seen in the sky from April to June. Crux is exactly opposite to Cassiopeia on the celestial sphere, and therefore it cannot be in the sky with the latter at the same time. For locations south of 34° southern latitude Crux is always completely in the sky.

If you use the Southern Cross to find south, be careful to distinguish it from the False Cross. The Southern Cross is somewhat kite-shaped, and it has a fifth star (ε Crucis). The False Cross is diamond-shaped and does not have a fifth star like ε Crucis.

Notable deep sky objects

The Coalsack Nebula is the most prominent dark nebula in the skies, easily visible to the naked eye as big dark patch in the southern Milky Way.

Another deep sky object within Crux is the Open Cluster NGC 4755, better known as the Jewel Box or Kappa Crucis Cluster, that was discovered by Nicolas Louis de Lacaille in 1751-1752. It lies at a distance of about 7,500 light years and consists of approximately 100 stars spread across an area of about 20 light-years square.

History

The Southern Cross, appearing on a number of flags and insignia.
Enlarge
The Southern Cross, appearing on a number of flags and insignia.

Due to precession of the equinox the stars comprising Crux were visible from the Mediterranean area in antiquity, so their stars had to be known by Greek astronomers. However, it was not regarded as a constellation of its own, but rather as part of Centaurus.

 A CTX image of crux.
Enlarge
A CTX image of crux.

The separation of Crux to be a separate constellation is generally attributed to the French astronomer Augustin Royer in 1679. Other historians attribute the invention of Crux to Petrus Plancius in 1613, and that the constellation was later published by Jakob Bartsch in 1624. However, Crux had already been a well known southern asterism at least four centuries before it was promoted to an official constellation and published in the Seventeenth Century.

The five brightest stars of Crux (α, β, γ, δ, and ε Crucis) appear on the flags of Australia, Brazil, New Zealand (epsilon omitted), Papua New Guinea, and Samoa, and also the Australian States and Territories of Victoria, the Australian Capital Territory, the Northern Territory, as well as the flag of Magallanes Region of Chile, and several Argentine provincial flags and emblems. The flag of the Mercosur trading zone displays the four brightest stars (epsilon omitted). Crux also appears on the Brazilian coat of arms. A stylized version of Crux appears on the Eureka Flag. The constellation was also used on the dark blue, shield-like patch worn by personnel of the U.S. Army's Americal Division, which was organized in the Southern Hemisphere, on the island of New Caledonia, and also the blue diamond of the U.S. 1st Marine Division, which fought on the Southern Hemisphere islands of Guadalcanal and New Britain.

Crux is important in Australian Aboriginal Astronomy. It, and the Coalsack, mark the head of the Emu in the sky in several Aboriginal cultures, while Crux itself is said to be a possum sitting in a tree.

A stone image of the constellation has also been left at the archaeological site of Machu Picchu, Peru.

In 1893, Australian Poet Banjo Paterson wrote : The English flag may flutter and wave, where the world wide oceans toss, but the flag the Australian dies to save, is the flag of the Southern Cross.

National Flags that have Crux on them

Other names for Crux

Crux is clearly visible above the aurora australis in this photograph taken from Dunedin, New Zealand. The red giant Gacrux is clearly a different colour to the other three main stars, which are blue-white
Enlarge
Crux is clearly visible above the aurora australis in this photograph taken from Dunedin, New Zealand. The red giant Gacrux is clearly a different colour to the other three main stars, which are blue-white
  • In ancient Hindu astrology, the modern Crux is referred to as "trishanku".
  • The Māori name for Crux is "Te Punga" - "the anchor". It is thought of as anchor of Tama-rereti's waka (the Milky Way), where the Pointers are its rope.
  • In Tonga it is known as Toloa — duck; it is a duck flying over, heading south, and one of his wings (δ) is wounded because Ongo tangata — 2 men — α and Β Centauri threw a stone at it. The Coalsack is known as Humu — triggerfish, because of its shape.[3]
  • Among Tuaregs, the 4 most visible stars of Crux are considered iggaren, i.e. four Maerua crassifolia trees.
  • In Indonesia and Malaysia,it is known as Buruj Pari (The Stingray).

In Australia and New Zealand, Crux is known as the Southern Cross.

External links and references

  1. ^ this star chart
  2. ^ this second star chart
  3. ^ Kik Velt; Stars over Tonga
The 88 modern constellations
Andromeda • Antlia • Apus • Aquarius • Aquila • Ara • Aries • Auriga • Boötes • Caelum • Camelopardalis • Cancer • Canes Venatici • Canis Major • Canis Minor • Capricornus • Carina • Cassiopeia • Centaurus • Cepheus • Cetus • Chamaeleon • Circinus • Columba • Coma Berenices • Corona Australis • Corona Borealis • Corvus • Crater • Crux • Cygnus • Delphinus • Dorado • Draco • Equuleus • Eridanus • Fornax • Gemini • Grus • Hercules • Horologium • Hydra • Hydrus • Indus • Lacerta • Leo • Leo Minor • Lepus • Libra • Lupus • Lynx • Lyra • Mensa • Microscopium • Monoceros • Musca • Norma • Octans • Ophiuchus • Orion • Pavo • Pegasus • Perseus • Phoenix • Pictor • Pisces • Piscis Austrinus • Puppis • Pyxis • Reticulum • Sagitta • Sagittarius • Scorpius • Sculptor • Scutum • Serpens • Sextans • Taurus • Telescopium • Triangulum • Triangulum Australe • Tucana • Ursa Major • Ursa Minor • Vela • Virgo • Volans • Vulpecula


Wikimedia Commons has media related to:

 
Shopping: Crux
Optimus Crux
 
 

Join the WikiAnswers Q&A community. Post a question or answer questions about "Crux" at WikiAnswers.

 

Copyrights:

Columbia Encyclopedia. The Columbia Electronic Encyclopedia, Sixth Edition Copyright © 2003, Columbia University Press. Licensed from Columbia University Press. All rights reserved. www.cc.columbia.edu/cu/cup/  Read more
WordNet. WordNet 1.7.1 Copyright © 2001 by Princeton University. All rights reserved.  Read more
Wikipedia. This article is licensed under the GNU Free Documentation License. It uses material from the Wikipedia article "Crux" Read more

Search for answers directly from your browser with the FREE Answers.com Toolbar!  
Click here to download now. 

Get Answers your way! Check out all our free tools and products.

On this page:   E-mail   print Print  Link  

 

Keep Reading

Mentioned In: