Crux

Crux

Constellation
List of stars in Crux
Abbreviation	Cru
Genitive	Crucis
Pronunciation	/ˈkrʌks/, genitive /ˈkruːsɨs/
Symbolism	Southern Cross
Right ascension	12.5 h
Declination	−60°
Quadrant	SQ3
Area	68 sq. deg. (88th)
Main stars	4
Bayer/Flamsteed stars	19
Stars with planets	1
Stars brighter than 3.00m	5
Stars within 10.00 pc (32.62 ly)	0
Brightest star	Acrux (α Cru) (0.87m)
Nearest star	η Cru (64.22 ly, 19.69 pc)
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 is the smallest of the 88 modern constellations, but is one of the most distinctive. Its name is Latin for cross, and it is dominated by a cross-shaped asterism that is commonly known as the Southern Cross.

Visibility

Being a circumpolar constellation, Crux is easily visible from the southern hemisphere at practically any time of year. It is also visible near the horizon from 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.

Location and identification

The five brightest stars in Crux are clearly visible in this picture. The red giant Gacrux and orange giant Juxta Crucem are distinctly different from the three other major stars of the constellation, which are Blue-white in colour

Contrary to popular belief, Crux 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°S, Crux is circumpolar and thus always visible in the night sky.

Crux is bordered by the constellations Centaurus, which surrounds it on three sides, and Musca.

Crux is sometimes confused with the nearby False Cross by stargazers. Crux is somewhat kite-shaped, and it has a fifth star (ε Crucis). The False Cross is diamond-shaped, somewhat dimmer on average, does not have a fifth star and lacks the two prominent "Pointer Stars."

Notable features

Stars

A CTX image of crux.

Stacked image of six identical frames of Crux.

Three of the five main Crux stars—–Acrux, Mimosa, and Delta Crucis—–are co-moving B-type members of the Scorpius-Centaurus Association, the nearest OB association to the Sun^[1]. They are among the highest-mass stellar members of the Lower Centaurus-Crux subgroup of the association, with ages of roughly 10 to 20 million years^[2][3].

Markers

Since the southern sky lacks an easily visible pole star, Alpha and Gamma (known as Acrux and Gacrux respectively) are commonly used to mark south. Tracing a line from Gacrux to Acrux and extending it for approximately 4.5 times the distance between the 2 stars 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 mentioned line and this line intersect marks the Southern Celestial Pole. The two stars of Alpha and Beta Centauri are often referred to as the "Southern Pointers" or just "The Pointers", allowing people to easily find the asterism of the Southern Cross or the constellation of Crux.

Named stars

• α is named Acrux, a concatenation of "Alpha" and "Crux" and named by American Elijah Burritt in the 19th Century.
• β is named Mimosa
• γ is named Gacrux, a concatenation of "Gamma" and "Crux"
• δ is the forth brightest star, but it has no designated name
• ε is the intruse, because it's inside the cross.

Deep sky objects

The Coalsack Nebula is the most prominent dark nebula in the skies, easily visible to the naked eye as a 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, that was discovered by Nicolas Louis de Lacaille in 1751–1752. It lies at a distance of 1.9±0.3 kiloparsecs or 6,900 light years and consists of approximately 100 stars spread across an area of about 20 square light-years.

History

Crux was visible to the Ancient Greeks, who regarded it as part of the constellation Centaurus. At the latitude of Athens in 1000 BC, Crux was clearly visible, though low in the sky. However, the precession of the equinoxes gradually lowered its stars below the European horizon, and they were eventually forgotten by the inhabitants of northern latitudes. By AD 400, most of the constellation never rose above the horizon for Athenians.

Crux was rediscovered by Europeans during the Age of Discovery. Amerigo Vespucci mapped Alpha Centauri and Beta Centauri as well as the stars of modern Crux on his expedition to South America in 1501.

The separation of Crux from Centaurus is generally attributed to the French astronomer Augustin Royer in 1679. Other historians attribute the invention of Crux to Petrus Plancius in 1613, noting that the constellation was later published by Jakob Bartsch in 1624.

Cultural significance

As a highly distinctive asterism, Crux has great significance in the cultures of the southern hemisphere.

In Australian Aboriginal astronomy, Crux 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 and a representation of the sky deity Mirrabooka.

In Australia it also has significance, it resides on fly of the national flag, and was on the Eureka Flag - the battle flag of the Eureka Stockade. It has since continued as a symbol of revolution against oppression, including both ends of the political spectrum, but mostly for its original association with class equality.

A stone image of the constellation has been found at the archaeological site of Machu Picchu, Peru. In Mapudungun, the language of Patagonian Mapuches, the name of Crux is Melipal, which means "four stars". In Quechua, the language of the Inca civilization, Crux is known as "Chakana", which means literally "stair" (chaka, bridge, link; hanan, high, above), but carries a deep symbolism within Quechua mysticism.^[4].

The Māori name for Crux is "Te Punga" – "the anchor". It is thought of as the 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—two men—α and Β Centauri threw a stone at it. The Coalsack is known as Humu—triggerfish, because of its shape.^[5] In Samoa the constellation is called "Sumu" (triggerfish) because of its rhomboid shape, while α and Β Centauri are called "Luatagata" (Two Men), as they are in Tonga.

In Indonesia and Malaysia, it is known as Buruj Pari (The Stingray). In ancient Hindu astrology, the modern Crux is referred to as "Trishanku".

Among Tuaregs, the four most visible stars of Crux are considered iggaren, i.e. four Maerua crassifolia trees.

Argentine Gauchos are well known for using it for night orientation in the vast Pampas and Patagonic regions. It is also of cultural significance, as it is referenced in several songs and literature, including the Martin Fierro.

The Southern Cross in popular culture

Cruzeiro Esporte Clube (Crux/Southern Cross Sport Club) is a very important football (soccer) club in Brazil.

The Nintendo game, StarTropics, for the NES features many references to and depictions of the Southern Cross.

The symbol of the Gryphus Squadron in Ace Combat X: Skies of Deception

The main character from the Namco game for the PlayStation Portable Ace Combat X: Skies of Deception who remains unnamed in the story but rather goes by his codename Gryphus-1 (as he is the leader of the Gryphus Squadron) is known as the "Southern Cross", and his symbol is an Andean Condor with the Southern Cross in its beak. Eugene Solano, his mission operator, is codenamed "Crux".

Melbourne's Southern Cross Hotel was built and named in 1962 and was one of the city's foremost hotels during the decade. The hotel was demolished in 2005 and replaced by the similarly named office building known as Southern Cross Tower.

"The Sign of the Southern Cross" is a Song by Black Sabbath written in 1981 which was sung by Ronnie James Dio.

"Southern Cross" is also a 1982 song by the classic rock group Crosby, Stills and Nash, written by Rick Curtis, Michael Curtis, and Stephen Stills. This song was also covered by Jimmy Buffett and is commonly played at his concerts.

Melbourne's Spencer Street Station was rebuilt and renamed "Southern Cross Station" in 2006.

The 1974 Australian America's Cup Challenger was named "Southern Cross" KA 4 representing the Royal Perth Yacht Club and was defeated 4-0 sailing off Newport Rhode Island by "Courageous" US26 sailing for the New York Yacht Club. Southern Cross became the trial horse for the 1977 Australian Challenger "Australia" KA 5 representing the Sun City Yacht Club that was defeated 4-0 sailing off Newport Rhode Island by Courageous US26 sailing for the New York Yacht Club.

The Argentine Air Force acrobatic display team is called Cruz del Sur, the Spanish for "Southern Cross".

"Crux" is the title of a 2009 album by instrumental artist Emmalee Crane. The album includes a song called "Stair Asterism" in reference to the Inca name for the constellation.

The manga and anime series Fist of The North Star has one of its major fighting style, Nanto Seiken, with the Crux as its symbol.

The Commonwealth Bank of Australia uses a stylized image of the Southern Cross as a corporate logo.

Zeitgeist movie claims that Sun can be at vicinity of Crux. This is not possible because Crux is not a zodiacal constellation.^[6] Zodiacal constellations are those where the Sun can be found.^[7]

Flags and symbols that incorporate Crux

Crux, appearing on a number of flags and insignia

Beginning in the colonial age, Crux became used as a national symbol by several southern nations. The brightest stars of Crux appear on the flags of Australia, Brazil, New Zealand, Papua New Guinea, and Samoa. They also appear on the flags of the Australian state 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 (e.g., Tierra del Fuego and Santa Cruz). The flag of the Mercosur trading zone displays the four brightest stars. Crux also appears on the Brazilian coat of arms.

The five stars are also in the logo of the Brazilian soccer team Cruzeiro Esporte Clube. 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.

•  Australia
•  Brazil
•  New Zealand
•  Niue
•  Papua New Guinea
•  Samoa
•  Tokelau

Cultural References to the flag symbol

In Australia, the Southern Cross played a crucial role as symbol of the Eureka Stockade. In the Eureka Oath from Peter Lalor's famous speech in 1854 under the flag he proclaimed:

We swear by the Southern Cross to stand truely by each other and fight to defend our rights and liberties.

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.

The Southern Cross was written into the lyrics of Advance Australia Fair in 1901; the song was adopted as the Australian National Anthem in 1984.

Beneath our radiant Southern Cross.

. The Southern Cross was written into the lyrics of the Brazilian National Anthem written in 1909,

A imagem do Cruzeiro resplandece. (the image of the (Southern Cross) shines resplendently.)

The victory song of the Australian national cricket team is entitled "Beneath the Southern Cross".

References

External links

• Letter of Andrea Corsali 1516-1989: with additional material ("the first description and illustration of the Southern Cross, with speculations about Australia ...") digitised by the National Library of Australia.
• The Deep Photographic Guide to the Constellations: Crux.
• The Cambridge Guide to the Constellations, Michael E. Bakich, Cambridge University Press, 1995, pg. 85.
• Universe: The Definitive Visual Dictionary, Robert Dinwiddie et al., DK Adult Publishing, (2005), pg. 396.
• The Sign of the Southern Cross Black Sabbath
• Ian Ridpath and Wil Tirion (2007). Stars and Planets Guide, Collins, London. ISBN 978-0007251209. Princeton University Press, Princeton. ISBN 978-0691135564.
• Southern Cross Starry Night Photography.
• Star Tales – Crux
• Finding the South Pole in the sky
• Southern Cross in Te Ara - the Encyclopedia of New Zealand
• [1]

Coordinates: 12^h 30^m 00^s, −60° 00′ 00″