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Crux

Crux is a constellation of the southern sky that is centred on four bright stars in a cross-shaped asterism commonly known as the Southern Cross. It lies on the southern end of the Milky Way's visible band. The name Crux is Latin for cross. Even though it is the smallest of all 88 modern constellations, Crux is among the most easily distinguished as its four main stars each have an apparent visual magnitude brighter than +2.8. It has attained a high level of cultural significance in many Southern Hemisphere states and nations.

Blue-white α Crucis (Acrux) is the most southerly member of the constellation and, at magnitude 0.8, the brightest. The three other stars of the cross appear clockwise and in order of lessening magnitude: β Crucis (Mimosa), γ Crucis (Gacrux), and δ Crucis (Imai). ε Crucis (Ginan) also lies within the cross asterism. Many of these brighter stars are members of the Scorpius–Centaurus association, a large but loose group of hot blue-white stars that appear to share common origins and motion across the southern Milky Way.

Crux contains four Cepheid variables, each visible to the naked eye under optimum conditions. Crux also contains the bright and colourful open cluster known as the Jewel Box (NGC 4755) on its eastern border. Nearby to the southeast is a large dark nebula spanning 7° by 5° known as the Coalsack Nebula, portions of which are mapped in the neighbouring constellations of Centaurus and Musca.

History
The bright stars in Crux were known to the Ancient Greeks, where Ptolemy regarded them as part of the constellation Centaurus. They were entirely visible as far north as Britain in the fourth millennium BC. However, the precession of the equinoxes gradually lowered the stars below the European horizon, and they were eventually forgotten by the inhabitants of northern latitudes. By 400 AD, the stars in the constellation now called Crux never rose above the horizon throughout most of Europe. Dante may have known about the constellation in the 14th century, as he describes an asterism of four bright stars in the southern sky in his Divine Comedy. His description, however, may be allegorical, and the similarity to the constellation a coincidence.

The 15th century Venetian navigator Alvise Cadamosto made note of what was probably the Southern Cross on exiting the Gambia River in 1455, calling it the carro dell'ostro ("southern chariot"). However, Cadamosto's accompanying diagram was inaccurate. Historians generally credit João Faras for being the first European to depict it correctly. Faras sketched and described the constellation (calling it "las guardas") in a letter written on the beaches of Brazil on 1 May 1500 to the Portuguese monarch.

Explorer Amerigo Vespucci seems to have observed not only the Southern Cross but also the neighboring Coalsack Nebula on his second voyage in 1501–1502.

Another early modern description clearly describing Crux as a separate constellation is attributed to Andrea Corsali, an Italian navigator who from 1515 to 1517 sailed to China and the East Indies in an expedition sponsored by King Manuel I. In 1516, Corsali wrote a letter to the monarch describing his observations of the southern sky, which included a rather crude map of the stars around the south celestial pole including the Southern Cross and the two Magellanic Clouds seen in an external orientation, as on a globe.

Emery Molyneux and Petrus Plancius have also been cited as the first uranographers (sky mappers) to distinguish Crux as a separate constellation; their representations date from 1592, the former depicting it on his celestial globe and the latter in one of the small celestial maps on his large wall map. Both authors, however, depended on unreliable sources and placed Crux in the wrong position. Crux was first shown in its correct position on the celestial globes of Petrus Plancius and Jodocus Hondius in 1598 and 1600. Its stars were first catalogued separately from Centaurus by Frederick de Houtman in 1603. The constellation was later adopted by Jakob Bartsch in 1624 and Augustin Royer in 1679. Royer is sometimes wrongly cited as initially distinguishing Crux.

Characteristics
Crux is bordered by the constellations Centaurus (which surrounds it on three sides) on the east, north and west, and Musca to the south. Covering 68 square degrees and 0.165% of the night sky, it is the smallest of the 88 constellations. The three-letter abbreviation for the constellation, as adopted by the International Astronomical Union in 1922, is "Cru". The official constellation boundaries, as set by Belgian astronomer Eugène Delporte in 1930, are defined by a polygon of four segments. In the equatorial coordinate system, the right ascension coordinates of these borders lie between 11:56.13:0 and 12:57.45:0, while the declination coordinates are between −55.68° and −64.70°. Its totality figures at least part of the year south of the 25th parallel north.

In tropical regions Crux can be seen in the sky from April to June. Crux is exactly opposite to Cassiopeia on the celestial sphere, and therefore it cannot appear in the sky with the latter at the same time. In this era, south of Cape Town, Adelaide, and Buenos Aires (the 34th parallel south), Crux is circumpolar and thus always appears in the sky.

Crux is sometimes confused with the nearby False Cross asterism by stargazers. The False Cross consists of stars in Carina and Vela, is larger and dimmer, does not have a fifth star, and lacks the two prominent nearby "Pointer Stars". Between the two is the even larger and dimmer Diamond Cross.

Visibility
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 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. 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
In the Southern Hemisphere, the Southern Cross is frequently used for navigation in much the same way that Polaris is used in the Northern Hemisphere. Projecting a line from γ to α Crucis (the foot of the crucifix) approximately $4 1/2$ times beyond gives a point close to the Southern Celestial Pole which is also, coincidentally, where 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. Argentine gauchos are documented as using Crux for night orientation in the Pampas 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.

Bright stars
Down to apparent magnitude +2.5 are 92 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).

Stars

Within the constellation's borders, there are 49 stars brighter than or equal to apparent magnitude 6.5. The four main stars that form the asterism are Alpha, Beta, Gamma, and Delta Crucis.
 * α Crucis or Acrux is a triple star 321 light-years from Earth. A rich blue in colour, with a visual magnitude 0.8 to the unaided eye, it has two close components of a similar magnitude, 1.3 and 1.8 respectively, plus another much wider component of the 5th magnitude. The two close components are resolved in a small amateur telescope and the wide component is readily visible in a pair of binoculars.
 * β Crucis or Mimosa is a blue-hued giant star of magnitude 1.3, and lies 353 light-years from Earth. It is a Beta Cephei-type variable star with a variation of less than 0.1 magnitudes.
 * γ Crucis or Gacrux is an optical double star. The primary is a red-hued giant star of magnitude 1.6, 88 light-years from Earth, and is one of the closest red giants to Earth. Its secondary component is magnitude 6.5, 264 light-years from Earth.
 * δ Crucis (Imai) is a magnitude 2.8 blue-white hued star about 345 light-years from Earth. Like Mimosa it is a Beta Cepheid variable.

There is also a fifth star, that is often included with the Southern Cross.
 * ε Crucis (Ginan) is an orange-hued giant star of magnitude 3.6, 228 light-years from Earth.

There are several other naked-eye stars within the borders of Crux, especially:
 * Iota Crucis is a visual double star 125 light-years from Earth. The primary is an orange-hued giant of magnitude 4.6 and the secondary at magnitude 9.5.
 * Mu Crucis or Mu1,2 Crucis is a wide double star where the components are about 370 light-years from Earth. Equally blue-white in colour, the components are magnitude 4.0 and 5.1 respectively, and are easily divisible in small amateur telescopes or large binoculars.

Scorpius–Centaurus association
Unusually, a total of 15 of the 23 brightest stars in Crux are spectrally blue-white B-type stars. Among the five main bright stars, Delta, and probably Alpha and Beta, are likely co-moving B-type members of the Scorpius–Centaurus association, the nearest OB association to the Sun. 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. Other members include the blue-white stars Zeta, Lambda and both the components of the visual double star, Mu.

Variable stars
Crux contains many variable stars. It boasts four Cepheid variables that may all reach naked eye visibility.
 * BG Crucis ranges from magnitude 5.34 to 5.58 over 3.3428 days,
 * T Crucis ranges from 6.32 to 6.83 over 6.73331 days,
 * S Crucis ranges from 6.22 to 6.92 over 4.68997 days,
 * R Crucis ranges from 6.4 to 7.23 over 5.82575 days.

Other well studied variable stars includes:
 * Lambda Crucis and Theta2 Crucis, that are both Beta Cepheid type variable stars.
 * BH Crucis, also known as Welch's Red Variable, is a Mira variable that ranges from magnitude 6.6 to 9.8 over 530 days. Discovered in October 1969, it has become redder and brighter (mean magnitude changing from 8.047 to 7.762) and its period lengthened by 25% in the first thirty years since its discovery.

Host star exoplanets in Crux
The star HD 106906 has been found to have a planet—HD 106906 b—that has one of the widest orbits of any currently known planetary-mass companions.

Objects beyond the Local Arm
Crux is backlit by the multitude of stars of the Scutum-Crux Arm (more commonly called the Scutum-Centaurus Arm) of the Milky Way. This is the main inner arm in the local radial quarter of the galaxy. Part-obscuring this is:
 * The Coalsack Nebula lies partially within Crux and partly in the neighboring constellations of Musca and Centaurus. It is the most prominent dark nebula in the skies, and is easily visible to the naked eye as a prominent dark patch in the southern Milky Way. It can be found 6.5° southeast from the centre of Crux or 3° east from α Crucis. Its large area covers about 7° by 5°, and is 180 pc away from Earth.

A key feature of the Scutum-Crux Arm is:
 * The Jewel Box, κ Crucis Cluster or NGC 4755, is a small but bright open cluster that appears as a fuzzy star to the naked eye and is very close to the easternmost boundary of Crux: about 1° southeast of Beta Crucis. The combined or total magnitude is 4.2 and it lies at a distance of 1.95 kpc from Earth. The cluster was given its name by John Herschel, based on the range of colours visible throughout the star cluster in his telescope. About seven million years old, it is one of the youngest open clusters in the Milky Way, and it appears to have the shape of a letter 'A'. The Jewel Box Cluster is classified as Shapley class 'g' and Trumpler class 'I 3 r -' cluster; it is a very rich, centrally-concentrated cluster detached from the surrounding star field. It has more than 100 stars that range significantly in brightness. The brightest cluster stars are mostly blue supergiants, though the cluster contains at least one red supergiant. Kappa Crucis is a true member of the cluster that bears its name, and is one of the brighter stars at magnitude 5.9.

Cultural significance
The most prominent feature of Crux is the distinctive asterism known as the Southern Cross. It has great significance in the cultures of the southern hemisphere, particularly of Australia, Brazil, Chile and New Zealand.

Flags and symbols
Several southern countries and organisations have traditionally used Crux as a national or distinctive symbol. The four or five brightest stars of Crux appear, heraldically standardised in various ways, 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, the flag of Londrina (Brazil) and several Argentine provincial flags and emblems (for example, 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 and,, on the cover of Brazilian passports.

Five stars appear in the logo of the Brazilian football team Cruzeiro Esporte Clube and in the insignia of the Order of the Southern Cross, and the cross has featured as name of the Brazilian currency (the cruzeiro from 1942 to 1986 and again from 1990 to 1994). All coins of the (1998) series of the Brazilian real display the constellation.

Songs and literature reference the Southern Cross, including the Argentine epic poem Martín Fierro. The Argentinian singer Charly García says that he is "from the Southern Cross" in the song "No voy en tren".

The Cross gets a mention in the lyrics of the Brazilian National Anthem (1909): "A imagem do Cruzeiro resplandece" ("the image of the Cross shines").

The Southern Cross is mentioned in the Australian National Anthem, "Beneath our radiant Southern Cross we'll toil with hearts and hands"

The Southern Cross features in the coat of arms of William Birdwood, 1st Baron Birdwood, the British officer who commanded the Australian and New Zealand Army Corps during the Gallipoli Campaign of the First World War.

The Southern Cross is also mentioned in the Samoan National Anthem. "Vaai 'i na fetu o lo'u a agiagia ai: Le faailoga lea o Iesu, na maliu ai mo Samoa." ("Look at those stars that are waving on it: This is the symbol of Jesus, who died on it for Samoa.")

The 1952-53 NBC Television Series Victory At Sea contained a musical number entitled "Beneath the Southern Cross".

"Southern Cross" is a single released by Crosby, Stills and Nash in 1981. It reached #18 on Billboard Hot 100 in late 1982.

"The Sign of the Southern Cross" is a song released by Black Sabbath in 1981. The song was released on the album "Mob Rules".

The Order of the Southern Cross is a Brazilian order of chivalry awarded to "those who have rendered significant service to the Brazilian nation".

In "O Sweet Saint Martin's Land", the lyrics mention the Southern Cross: Thy Southern Cross the night.

A stylized version of Crux appears on the Australian 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 on the blue diamond of the U.S. 1st Marine Division, which fought on the Southern Hemisphere islands of Guadalcanal and New Britain.

The Petersflagge flag of the German East Africa Company of 1885–1920, which included a constellation of five white five-pointed Crux "stars" on a red ground, later served as the model for symbolism associated with generic German colonial-oriented organisations: the Reichskolonialbund of 1936–1943 and the Friends of the former German Protectorates (1956/1983 to the present).

Southern Cross station is a major rail terminal in Melbourne, Australia.

The Personal Ordinariate of Our Lady of the Southern Cross is a personal ordinariate of the Roman Catholic Church primarily within the territory of the Australian Catholic Bishops Conference for groups of Anglicans who desire full communion with the Catholic Church in Australia and Asia.

The Knights of the Southern Cross (KSC) is a Catholic fraternal order throughout Australia.

Various cultures
In India, there is a story related to the creation of Trishanku Swarga (त्रिशंकु), meaning Cross (Crux), created by Sage Vishwamitra.

In Chinese, 十字架 (Shí Zì Jià), meaning Cross, refers to an asterism consisting of γ Crucis, α Crucis, β Crucis and δ Crucis.

In Australian Aboriginal astronomy, Crux and the Coalsack mark the head of the 'Emu in the Sky' (which is seen in the dark spaces rather than in the patterns of stars) in several Aboriginal cultures, while Crux itself is said to be a possum sitting in a tree (Boorong people of the Wimmera region of northwestern Victoria), a representation of the sky deity Mirrabooka (Quandamooka people of Stradbroke Island), a stingray (Yolngu people of Arnhem Land), or an eagle (Kaurna people of the Adelaide Plains). Two Pacific constellations also included Gamma Centauri. Torres Strait Islanders in modern-day Australia saw Gamma Centauri as the handle and the four stars as the left hand of Tagai, and the stars of Musca as the trident of the fishing spear he is holding. In Aranda traditions of central Australia, the four Cross stars are the talon of an eagle and Gamma Centauri as its leg.

Various peoples in the East Indies and Brazil viewed the four main stars as the body of a ray. In both Indonesia and Malaysia, it is known as Bintang Pari and Buruj Pari, respectively ("ray stars"). This aquatic theme is also shared by an archaic name of the constellation in Vietnam, where it was once known as sao Cá Liệt (the ponyfish star).

Among Filipino people, the southern cross have various names pertaining to tops, including kasing (Visayan languages), paglong (Bikol), and pasil (Tagalog). It is also called butiti (puffer fish) in Waray.

The Javanese people of Indonesia called this constellation Gubug pèncèng ("raking hut") or lumbung ("the granary"), because the shape of the constellation was like that of a raking hut.

The Southern Cross (α, β, γ and δ Crucis) together with μ Crucis is one of the asterisms used by Bugis sailors for navigation, called bintoéng bola képpang, meaning "incomplete house star"

The Māori name for the Southern Cross is Māhutonga and it is thought of as the anchor (Te Punga) of Tama-rereti's waka (the Milky Way), while the Pointers are its rope. In Tonga it is known as Toloa ("duck"); it is depicted as a duck flying south, with one of his wings (δ Crucis) wounded because Ongo tangata ("two men", α and β Centauri) threw a stone at it. The Coalsack is known as Humu (the "triggerfish"), because of its shape. In Samoa the constellation is called Sumu ("triggerfish") because of its rhomboid shape, while α and β Centauri are called Luatagata (Two Men), just as they are in Tonga. The peoples of the Solomon Islands saw several figures in the Southern Cross. These included a knee protector and a net used to catch Palolo worms. Neighboring peoples in the Marshall Islands saw these stars as a fish. Peninsular Malays also see the likeness of a fish in the Crux, particularly the Scomberomorus or its local name Tohok.

In Mapudungun, the language of Patagonian Mapuches, the name of the Southern Cross 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. Alpha and Beta Crucis make up one foot of the Great Rhea, a constellation encompassing Centaurus and Circinus along with the two bright stars. The Great Rhea was a constellation of the Bororo of Brazil. The Mocoví people of Argentina also saw a rhea including the stars of Crux. Their rhea is attacked by two dogs, represented by bright stars in Centaurus and Circinus. The dogs' heads are marked by Alpha and Beta Centauri. The rhea's body is marked by the four main stars of Crux, while its head is Gamma Centauri and its feet are the bright stars of Musca. The Bakairi people of Brazil had a sprawling constellation representing a bird snare. It included the bright stars of Crux, the southern part of Centaurus, Circinus, at least one star in Lupus, the bright stars of Musca, Beta and the optical double star Delta1,2 Chamaeleontis: and some of the stars of Volans, and Mensa. The Kalapalo people of Mato Grosso state in Brazil saw the stars of Crux as Aganagi angry bees having emerged from the Coalsack, which they saw as the beehive.

Among Tuaregs, the four most visible stars of Crux are considered iggaren, i.e. four Maerua crassifolia trees. The Tswana people of Botswana saw the constellation as Dithutlwa, two giraffes – Alpha and Beta Crucis forming a male, and Gamma and Delta forming the female.

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Cepheus

Cepheus (Ancient Greek: Κηφεύς Kepheús) may refer to:

In Greek mythology

 * Cepheus (father of Andromeda), and King of Aethiopia
 * Cepheus (son of Aleus), a king of Tegea, Arcadia

In astronomy

 * Cepheus (constellation), one of the 88 modern constellations
 * Cepheus (crater), a lunar impact crater

In Computing

 * Cepheus (poker bot)

In modern fiction

 * Cepheus Daidalos, a fictional character in the manga and anime, Saint Seiya
 * Cepheus, the FM king in Mega Man Star Force
 * In the Galaxy Railways, one of the squads is named the Cepheus Platoon.

Other uses

 * USS Cepheus (AKA-18), an Andromeda class attack cargo ship

license: Creative Commons - Attribution Share-Alike - https://creativecommons.org/licenses/by-sa/4.0/

title: Cepheus


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Cassiopeia

Cassiopeia or Cassiopea may refer to:

Greek mythology

 * Cassiopeia (mother of Andromeda), queen of Aethiopia and mother of Andromeda
 * Cassiopeia (wife of Phoenix), wife of Phoenix, king of Phoenicia
 * Cassiopeia, wife of Epaphus, king of Egypt, the son of Zeus and Io; mother of Libya

Science

 * Cassiopeia (constellation), a northern constellation representing the queen of Ethiopia
 * Cassiopeia A, a supernova remnant in that constellation
 * Cassiopea, the genus of the "upside-down" jellyfish

Film

 * Cassiopeia (1996 film), a Brazilian CGI film
 * Cassiopeia (2022 film), a South Korean film

Music

 * Cassiopeia (TVXQ), the fan club of South Korean boy band TVXQ
 * "Cassiopeia", a song by Shabütie (now known as Coheed and Cambria) from their 1999 EP The Penelope EP
 * "Cassiopeia", a song by Joanna Newsom from her 2004 album The Milk-Eyed Mender
 * "Cassiopeia", a song by Dragonland from their 2006 album Astronomy
 * "Cassiopeia", a song by Sunny Lax from his 2006 EP P.U.M.A./Cassiopeia
 * "Cassiopeia", a song by Rain from his 2006 album Rain's World
 * "Cassiopeia", a song by Sara Bareilles from her 2013 album The Blessed Unrest

Fictional characters

 * Cassiopeia "Cassie" Sullivan, in The 5th Wave series written by Rick Yancey
 * Cassiopeia, a magical tortoise in Michael Ende's fantasy novel Momo
 * Cassiopeia (Battlestar Galactica), from the television series Battlestar Galactica
 * Cassiopea (Encantadia), the first Queen of Lireo in the Encantadia fantasy series of GMA Network
 * Cassiopeia, the mother of Octavian in The Astonishing Life of Octavian Nothing
 * Cassiopeia, the organizer and leader of "Operation Starfall" in the Starfall Street storyline in Pokémon Scarlet and Violet

Other

 * Casio Cassiopeia, a series of pocket PCs
 * Cassiopeia (train), an overnight rail service in Japan
 * USS Cassiopeia (AK-75), a cargo ship used by the United States Navy in World War II

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Cetus

Cetus is a constellation, sometimes called 'the whale' in English. The Cetus was a sea monster in Greek mythology which both Perseus and Heracles needed to slay. Cetus is in the region of the sky that contains other water-related constellations: Aquarius, Pisces and Eridanus.

Ecliptic
Cetus is not among the 12 true zodiac constellations in the J2000 epoch, nor classical 12-part zodiac. The ecliptic passes less than 0.25° from one of its corners. Thus the moon and planets will enter Cetus (occulting any stars as a foreground object) in 50% of their successive orbits briefly and the southern part of the sun appears in Cetus for about one day each year. Many asteroids in belts have longer phases occulting the north-western part of Cetus, those with a slightly greater inclination to the ecliptic than the moon and planets.

As seen from Mars, the ecliptic (apparent plane of the sun and also the average plane of the planets which is almost the same) passes into it.

Stars
Mira ("wonderful", named by Bayer: Omicron Ceti, a star of the neck of the asterism) was the first variable star to be discovered and the prototype of its class, Mira variables. Over a period of 332 days, it reaches a maximum apparent magnitude of 3 - visible to the naked eye - and dips to a minimum magnitude of 10, invisible to the unaided eye. Its seeming appearance and disappearance gave it its name. Mira pulsates with a minimum size of 400 solar diameters and a maximum size of 500 solar diameters. 420 light-years from Earth, it was discovered by David Fabricius in 1596.

α Ceti, traditionally called Menkar ("the nose"), is a red-hued giant star of magnitude 2.5, 220 light-years from Earth. It is a wide double star; the secondary is 93 Ceti, a blue-white hued star of magnitude 5.6, 440 light-years away. β Ceti, also called Deneb Kaitos and Diphda is the brightest star in Cetus. It is an orange-hued giant star of magnitude 2.0, 96 light-years from Earth. The traditional name "Deneb Kaitos" means "the whale's tail". γ Ceti, Kaffaljidhma ("head of the whale") is a very close double star. The primary is a yellow-hued star of magnitude 3.5, 82 light-years from Earth, and the secondary is a blue-hued star of magnitude 6.6. Tau Ceti is noted for being a near Sun-like star at a distance of 11.9 light-years. It is a yellow-hued main-sequence star of magnitude 3.5.

AA Ceti is a triple star system; the brightest member has a magnitude of 6.2. The primary and secondary are separated by 8.4 arcseconds at an angle of 304 degrees. The tertiary is not visible in telescopes. AA Ceti is an eclipsing variable star; the tertiary star passes in front of the primary and causes the system's apparent magnitude to decrease by 0.5 magnitudes. UV Ceti is an unusual binary variable star. 8.7 light-years from Earth, the system consists of two red dwarfs. Both of magnitude 13. One of the stars is a flare star, which are prone to sudden, random outbursts that last several minutes; these increase the pair's apparent brightness significantly - as high as magnitude 7.

Deep-sky objects
Cetus lies far from the galactic plane, so that many distant galaxies are visible, unobscured by dust from the Milky Way. Of these, the brightest is Messier 77 (NGC 1068), a 9th magnitude spiral galaxy near Delta Ceti. It appears face-on and has a clearly visible nucleus of magnitude 10. About 50 million light-years from Earth, M77 is also a Seyfert galaxy and thus a bright object in the radio spectrum. Recently, the galactic cluster JKCS 041 was confirmed to be the most distant cluster of galaxies yet discovered.

The massive cD galaxy Holmberg 15A is also found in Cetus; as is spiral galaxy NGC 1042 and ultra-diffuse galaxy NGC 1052-DF2.

IC 1613 (Caldwell 51) is an irregular dwarf galaxy near the star 26 Ceti and is a member of the Local Group.

NGC 246 (Caldwell 56), also called the Cetus Ring, is a planetary nebula with a magnitude of 8.0, 1600 light-years from Earth. Among some amateur astronomers, NGC 246 has garnered the nickname "Pac-Man Nebula" because of the arrangement of its central stars and the surrounding star field.

The Wolf–Lundmark–Melotte (WLM) is a barred irregular galaxy discovered in 1909 by Max Wolf, located on the outer edges of the Local Group. The discovery of the nature of the galaxy was accredited to Knut Lundmark and Philibert Jacques Melotte in 1926.

UGC 1646 spiral galaxy also lies between the borders of the constellation. It is about 150 million light-years away from us. It can be seen near TYC 43-234-1 star.

History and mythology
Cetus may have originally been associated with a whale, which would have had mythic status amongst Mesopotamian cultures. It is often now called the Whale, though it is most strongly associated with Cetus the sea-monster, who was slain by Perseus as he saved the princess Andromeda from Poseidon's wrath. It is in the middle of "The Sea" recognised by mythologists, a set of water-associated constellations, its other members being Eridanus, Pisces, Piscis Austrinus and Aquarius.

Cetus has been depicted in many ways throughout its history. In the 17th century, Cetus was depicted as a "dragon fish" by Johann Bayer. Both Willem Blaeu and Andreas Cellarius depicted Cetus as a whale-like creature in the same century. However, Cetus has also been variously depicted with animal heads attached to a piscine body.

In global astronomy
In Chinese astronomy, the stars of Cetus are found among two areas: the Black Tortoise of the North (北方玄武, Běi Fāng Xuán Wǔ) and the White Tiger of the West (西方白虎, Xī Fāng Bái Hǔ).

The Tukano and Kobeua people of the Amazon used the stars of Cetus to create a jaguar, representing the god of hurricanes and other violent storms. Lambda, Mu, Xi, Nu, Gamma, and Alpha Ceti represented its head; Omicron, Zeta, and Chi Ceti represented its body; Eta Eri, Tau Cet, and Upsilon Cet marked its legs and feet; and Theta, Eta, and Beta Ceti delineated its tail.

In Hawaii, the constellation was called Na Kuhi, and Mira (Omicron Ceti) may have been called Kane.

Namesakes
USS Cetus (AK-77) was a United States Navy Crater class cargo ship named after the constellation.

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Carina (constellation)

Carina is a constellation in the southern sky. Its name is Latin for the keel of a ship, and it was the southern foundation of the larger constellation of Argo Navis (the ship Argo) until it was divided into three pieces, the other two being Puppis (the poop deck), and Vela (the sails of the ship).

History and mythology
Carina was once a part of Argo Navis, the great ship of the mythical Jason and the Argonauts who searched for the Golden Fleece. The constellation of Argo was introduced in ancient Greece. However, due to the massive size of Argo Navis and the sheer number of stars that required separate designation, Nicolas-Louis de Lacaille divided Argo into three sections in 1763, including Carina (the hull or keel). In the 19th century, these three became established as separate constellations, and were formally included in the list of 88 modern IAU constellations in 1930. Lacaille kept a single set of Greek letters for the whole of Argo, and separate sets of Latin letter designations for each of the three sections. Therefore, Carina has the α, β and ε, Vela has γ and δ, Puppis has ζ, and so on.

Stars
Carina contains Canopus, a white-hued supergiant that is the second-brightest star in the night sky at magnitude −0.72. Alpha Carinae, as Canopus is formally designated, is 313 light-years from Earth. Its traditional name comes from the mythological Canopus, who was a navigator for Menelaus, king of Sparta.

There are several other stars above magnitude 3 in Carina. Beta Carinae, traditionally called Miaplacidus, is a blue-white-hued star of magnitude 1.7, 111 light-years from Earth. Epsilon Carinae is an orange-hued giant star similarly bright to Miaplacidus at magnitude 1.9; it is 630 light-years from Earth. Another fairly bright star is the blue-white-hued Theta Carinae; it is a magnitude 2.7 star 440 light-years from Earth. Theta Carinae is also the most prominent member of the cluster IC 2602. Iota Carinae is a white-hued supergiant star of magnitude 2.2, 690 light-years from Earth.

Eta Carinae is the most prominent variable star in Carina, with a mass of approximately 100 solar masses and 4 million times as bright as the Sun. It was first discovered to be unusual in 1677, when its magnitude suddenly rose to 4, attracting the attention of Edmond Halley. Eta Carinae is inside NGC 3372, commonly called the Carina Nebula. It had a long outburst in 1827, when it brightened to magnitude 1, only fading to magnitude 1.5 in 1828. Its most prominent outburst made Eta Carinae the equal of Sirius; it brightened to magnitude −1.5 in 1843. In the decades following 1843 it appeared relatively placid, having a magnitude between 6.5 and 7.9. However, in 1998, it brightened again, though only to magnitude 5.0, a far less drastic outburst. Eta Carinae is a binary star, with a companion that has a period of 5.5 years; the two stars are surrounded by the Homunculus Nebula, which is composed of gas that was ejected in 1843.

There are several less prominent variable stars in Carina. l Carinae is a Cepheid variable noted for its brightness; it is the brightest Cepheid that is variable to the unaided eye. It is a yellow-hued supergiant star with a minimum magnitude of 4.2 and a maximum magnitude of 3.3; it has a period of 35.5 days.

Two bright Mira variable stars are in Carina: R Carinae and S Carinae; both stars are red giants. R Carinae has a minimum magnitude of 10.0 and a maximum magnitude of 4.0. Its period is 309 days and it is 416 light-years from Earth. S Carinae is similar, with a minimum magnitude of 10.0 and a maximum magnitude of 5.0. However, S Carinae has a shorter period—150 days, though it is much more distant at 1,300 light-years from Earth.

Carina is home to several double stars and binary stars. Upsilon Carinae is a binary star with two blue-white-hued giant components, 1,600 light-years from Earth. The primary is of magnitude 3.0 and the secondary is of magnitude 6.0; the two components are distinguishable in a small amateur telescope. Two asterisms are prominent in Carina. The 'Diamond Cross' is composed of the stars Beta, Theta, Upsilon and Omega Carinae. The Diamond Cross is visible south of 20ºN latitude, and is larger but fainter than the Southern Cross in Crux. Flanking the Diamond Cross is the False cross, composed of four stars - two stars in Carina, Iota Carinae and Epsilon Carinae, and two stars in Vela, Kappa Velorum and Delta Velorum - and is often mistaken for the Southern Cross, causing errors in astronavigation.

Deep-sky objects
Carina is known for its namesake nebula, NGC 3372, discovered by French astronomer Nicolas-Louis de Lacaille in 1751, which contains several nebulae. The Carina Nebula overall is an extended emission nebula approximately 8,000 light-years away and 300 light-years wide that includes vast star-forming regions. It has an overall magnitude of 8.0 and an apparent diameter of over 2 degrees. Its central region is called the Keyhole, or the Keyhole Nebula. This was described in 1847 by John Herschel, and likened to a keyhole by Emma Converse in 1873. The Keyhole is about seven light-years wide and is composed mostly of ionized hydrogen, with two major star-forming regions. The Homunculus Nebula is a planetary nebula visible to the naked eye that is being ejected by the erratic luminous blue variable star Eta Carinae, the most massive visible star known. Eta Carinae is so massive that it has reached the theoretical upper limit for the mass of a star and is therefore unstable. It is known for its outbursts; in 1840 it briefly became one of the brightest stars in the sky due to a particularly massive outburst, which largely created the Homunculus Nebula. Because of this instability and history of outbursts, Eta Carinae is considered a prime supernova candidate for the next several hundred thousand years because it has reached the end of its estimated million-year life span.

NGC 2516 is an open cluster that is both quite large (approximately half a degree square) and bright, visible to the unaided eye. It is located 1,100 light-years from Earth and has approximately 80 stars, the brightest of which is a red giant star of magnitude 5.2. NGC 3114 is another open cluster approximately of the same size, though it is more distant at 3,000 light-years from Earth. It is more loose and dim than NGC 2516, as its brightest stars are only 6th magnitude. The most prominent open cluster in Carina is IC 2602, also called the "Southern Pleiades". It contains Theta Carinae, along with several other stars visible to the unaided eye. In total, the cluster possesses approximately 60 stars. The Southern Pleiades is particularly large for an open cluster, with a diameter of approximately one degree. Like IC 2602, NGC 3532 is visible to the unaided eye and is of comparable size. It possesses approximately 150 stars that are arranged in an unusual shape, approximating an ellipse with a dark central area. Several prominent orange giants are among the cluster's bright stars, of the 7th magnitude. Superimposed on the cluster is Chi Carinae, a yellow-white-hued star of magnitude 3.9, far more distant than NGC 3532.

Carina also contains the naked-eye globular cluster NGC 2808. Epsilon Carinae and Upsilon Carinae are double stars visible in small telescopes.

One noted galaxy cluster is 1E 0657-56, the Bullet Cluster. At a distance of 4 billion light-years (redshift 0.296), this galaxy cluster is named for the shock wave seen in the intracluster medium, which resembles the shock wave of a supersonic bullet. The bow shock visible is thought to be due to the smaller galaxy cluster moving through the intracluster medium at a relative speed of 3,000–4,000 kilometers per second to the larger cluster. Because this gravitational interaction has been ongoing for hundreds of millions of years, the smaller cluster is being destroyed and will eventually merge with the larger cluster.

Meteors
Carina contains the radiant of the Eta Carinids meteor shower, which peaks around January 21 each year.

Equivalents
From China (especially northern China), the stars of Carina can barely be seen. The star Canopus (the south polar star in Chinese astronomy) was located by Chinese astronomers in the Vermilion Bird of the South (南方朱雀, Nán Fāng Zhū Què). The rest of the stars were first classified by Xu Guanggi during the Ming dynasty, based on the knowledge acquired from western star charts, and placed among The Southern Asterisms (近南極星區, Jìnnánjíxīngōu).

Polynesian peoples had no name for the constellation in particular, though they had many names for Canopus. The Māori name Ariki ("High-born"), and the Hawaiian Ke Alii-o-kona-i-ka-lewa, "The Chief of the southern expanse" both attest to the star's prominence in the southern sky, while the Māori Atutahi, "First-light" or "Single-light", and the Tuamotu Te Tau-rari and Marere-te-tavahi, "He who stands alone". refer to the star's solitary nature. It was also called Kapae-poto ("Short horizon"), because it rarely sets from the vantage point of New Zealand, and Kauanga ("Solitary"), when it was the last star visible before sunrise.

Future
Carina is in the southern sky quite near the south celestial pole, making it never set (circumpolar) for most of the southern hemisphere. Due to precession of Earth's axis, by the year 4700 the south celestial pole will be in Carina. Three bright stars in Carina will come within 1 degree of the southern celestial pole and take turns as the southern pole star: Omega Carinae (mag 3.29) in 5600, Upsilon Carinae (mag 2.97) in 6700, and Iota Carinae (mag 2.21) in 7900. About 13,860 CE, the bright Canopus (−0.7) will have a greater declination than −82°.

Namesakes
USS Carina (AK-74) was a United States Navy Crater-class cargo ship named after the constellation.

the Toyota Carina was named after it.

title: Carina (constellation)


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Camelopardalis

Camelopardalis is a large but faint constellation of the northern sky representing a giraffe. The constellation was introduced in 1612 or 1613 by Petrus Plancius. Some older astronomy books give Camelopardalus or Camelopardus as alternative forms of the name, but the version recognized by the International Astronomical Union matches the genitive form, seen suffixed to most of its key stars.

Etymology
First attested in English in 1785, the word camelopardalis comes from Latin, and it is the romanization of the Greek "καμηλοπάρδαλις" meaning "giraffe", from "κάμηλος" (kamēlos), "camel" + "πάρδαλις" (pardalis), "spotted", because it has a long neck like a camel and spots like a leopard.

Stars
Although Camelopardalis is the 18th largest constellation, it is not a particularly bright constellation, as the brightest stars are only of fourth magnitude. In fact, it only contains four stars brighter than magnitude 5.0.

 * α Cam is a blue-hued supergiant star of magnitude 4.3, over 6,000 light-years from Earth. It is one of the most distant stars easily visible with the naked eye.
 * β Cam is the brightest star in Camelopardalis with an apparent magnitude of 4.03. This star is a double star, with components of magnitudes 4.0 and 8.6. The primary is a yellow-hued supergiant 1000 light-years from Earth.
 * 11 Cam is a star of magnitude 5.2, 650 light-years from Earth. It appears without intense magnification very close to magnitude 6.1 12 Cam, at about the same distance from us, but the two are not a true double star; they have considerable separation.
 * Σ 1694 (Struve 1694, 32 Cam) is a binary star 300 light-years from Earth. Both components have a blue-white hue; the primary is of magnitude 5.4 and the secondary is of magnitude 5.9.
 * CS Cam is the second brightest star, though it has neither a Bayer nor a Flamsteed designation. It is of magnitude 4.21 and is slightly variable.
 * Z Cam (varying from amateur telescope visibility to extremely faint) is frequently observed as part of a program of AAVSO. It is the prototype of Z Camelopardalis variable stars.

Other variable stars are U Camelopardalis, VZ Camelopardalis, and Mira variables T Camelopardalis, X Camelopardalis, and R Camelopardalis. RU Camelopardalis is one of the brighter Type II Cepheids visible in the night sky.

In 2011 a supernova was discovered in the constellation.

Deep-sky objects
Camelopardalis is in the part of the celestial sphere facing away from the galactic plane. Accordingly, many distant galaxies are visible within its borders.
 * NGC 2403 is a galaxy in the M81 group of galaxies, located approximately 12 million light-years from Earth with a redshift of 0.00043. It is classified as being between an elliptical and a spiral galaxy because it has faint arms and a large central bulge. NGC 2403 was first discovered by the 18th century astronomer William Herschel, who was working in England at the time. It has an integrated magnitude of 8.0 and is approximately 0.25° long.
 * NGC 1502 is a magnitude 6.9 open cluster about 3,000 light years from Earth. It has about 45 bright members, and features also a double star of magnitude 7.0 at its center. NGC 1502 is also associated with Kemble's Cascade, a simple but beautiful asterism appearing in the sky as a chain of stars 2.5° long that is parallel to the Milky Way and is pointed towards Cassiopeia. * NGC 1501 is a planetary nebula located roughly 1.4° south of NGC 1502.
 * Stock 23 is an open star cluster at the southern part of the border between Camelopardalis and Cassiopeia. It is also known as Pazmino's Cluster. It could be categorized as an asterism because of the small number of stars in it (a small telescopic constellation).
 * IC 342 is one of the brightest two galaxies in the IC 342/Maffei Group of galaxies.
 * The dwarf irregular galaxy NGC 1569 is a magnitude 11.9 starburst galaxy, about 11 million light years away.
 * NGC 2655 is a large lenticular galaxy with visual magnitude 10.1.
 * UGC 3697 is known as the Integral Sign Galaxy (its location is 7:11:4 / +71°50').
 * MS0735.6+7421 is a galaxy cluster with a redshift of 0.216, located 2.6 billion light-years from Earth. It is unique for its intracluster medium, which emits X-rays at a very high rate. This galaxy cluster features two cavities 600,000 light-years in diameter, caused by its central supermassive black hole, which emits jets of matter. MS0735.6+7421 is one of the largest and most distant examples of this phenomenon.
 * Tombaugh 5 is a fairly dim open cluster in Camelopardalis. It has an overall magnitude of 8.4 and is located 5,800 light-years from Earth. It is a Shapley class c and Trumpler class III 1 r cluster, meaning that it is irregularly shaped and appears loose. Though it is detached from the star field, it is not concentrated at its center at all. It has more than 100 stars which do not vary widely in brightness, mostly being of the 15th and 16th magnitude.
 * NGC 2146 is an 11th magnitude barred spiral starburst galaxy conspicuously warped by interaction with a neighbour.
 * MACS0647-JD, one of the possible candidates for the farthest known galaxies in the universe (z= 10.7), is also in Camelopardalis.

Meteor showers
The annual May meteor shower Camelopardalids from comet 209P/LINEAR have a radiant in Camelopardalis.

History

Camelopardalis is not one of Ptolemy's 48 constellations in the Almagest. It was created by Petrus Plancius in 1613. It first appeared in a globe designed by him and produced by Pieter van den Keere. One year later, Jakob Bartsch featured it in his atlas. Johannes Hevelius depicted this constellation in his works which were so influential that it was referred to as Camelopardali Hevelii or abbreviated as Camelopard. Hevel.

Part of the constellation was hived off to form the constellation Sciurus Volans, the Flying Squirrel, by William Croswell in 1810. However this was not taken up by later cartographers.

Equivalents
In Chinese astronomy, the stars of Camelopardalis are located within a group of circumpolar stars called the Purple Forbidden Enclosure (紫微垣 Zǐ Wēi Yuán).

title: Camelopardalis


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Convention of Kanagawa

The Convention of Kanagawa, also known as the Kanagawa Treaty (神奈川条約, Kanagawa Jōyaku) or the Japan–US Treaty of Peace and Amity (日米和親条約, Nichibei Washin Jōyaku), was a treaty signed between the United States and the Tokugawa Shogunate on March 31, 1854. Signed under threat of force, it effectively meant the end of Japan's 220-year-old policy of national seclusion (sakoku) by opening the ports of Shimoda and Hakodate to American vessels. It also ensured the safety of American castaways and established the position of an American consul in Japan. The treaty precipitated the signing of similar treaties establishing diplomatic relations with other Western powers.

Isolation of Japan
Since the beginning of the 17th century, the Tokugawa Shogunate pursued a policy of isolating the country from outside influences. Foreign trade was maintained only with the Dutch and the Chinese and was conducted exclusively at Nagasaki under a strict government monopoly. This "Pax Tokugawa" period is largely associated with domestic peace, social stability, commercial development, and expanded literacy. This policy had two main objectives:

 * 1) To suppress the spread of Christianity. By the early 17th century, Catholicism had spread throughout the world. Tokugawa feared that trade with western powers would cause further instability in the nation. Thus, the isolation policy expelled foreigners and did not allow international travel.
 * 2) The Japanese feared that foreign trade and the wealth developed would lead to the rise of a daimyō powerful enough to overthrow the ruling Tokugawa clan, especially after seeing what happened to China during the Opium Wars.

By the early 19th century, this policy of isolation was increasingly under challenge. In 1844, King William II of the Netherlands sent a letter urging Japan to end the isolation policy on its own before change would be forced from the outside. In 1846, an official American expedition led by Commodore James Biddle arrived in Japan asking for ports to be opened for trade but was sent away.

Perry expedition
In 1853, United States Navy Commodore Matthew C. Perry was sent with a fleet of warships by U.S. President Millard Fillmore to force the opening of Japanese ports to American trade, through the use of gunboat diplomacy if necessary. President Fillmore's letter shows the U.S. sought trade with Japan to open export markets for American goods like gold from California, enable U.S. ships to refuel in Japanese ports, and secure protections and humane treatment for any American sailors shipwrecked on Japan's shores. The growing commerce between America and China, the presence of American whalers in waters offshore Japan, and the increasing monopolization of potential coaling stations by the British and French in Asia were all contributing factors. The Americans were also driven by concepts of manifest destiny and the desire to impose the perceived benefits of western civilization and Christianity on what they perceived as backward Asian nations. From the Japanese perspective, increasing contacts with foreign warships and the increasing disparity between western military technology and the Japanese feudal armies fostered growing concern. The Japanese had been keeping abreast of world events via information gathered from Dutch traders in Dejima and had been forewarned by the Dutch of Perry's voyage. There was a considerable internal debate in Japan on how best to meet this potential threat to Japan's economic and political sovereignty in light of events occurring in China with the Opium Wars.

Perry arrived with four warships at Uraga, at the mouth of Edo Bay on July 8, 1853. He blatantly refused Japanese demands that he proceed to Nagasaki, which was the designated port for foreign contact. After threatening to continue directly on to Edo, the nation's capital, and to burn it to the ground if necessary, he was allowed to land at nearby Kurihama on July 14 and to deliver his letter. Such refusal was intentional, as Perry wrote in his journal: “To show these princes how little I regarded their order for me to depart, on getting on board I immediately ordered the whole squadron underway, not to leave the bay… but to go higher up… would produce a decided influence upon the pride and conceit of the government, and cause a more favorable consideration of the President’s letter." Perry's power front did not stop with refusing to land in Uraga, but he continued to push the boundaries of the Japanese. He ordered the squadron to survey Edo bay, which led to a stand-off between Japanese officers with swords and Americans with guns. By firing the guns into the water, Perry demonstrated their military might, which greatly affected Japanese perceptions of Perry and the United States. Namely, a perception of fear and disrespect.

Despite years of debate on the isolation policy, Perry's letter created great controversy within the highest levels of the Tokugawa shogunate. The shōgun himself, Tokugawa Ieyoshi, died days after Perry's departure and was succeeded by his sickly young son, Tokugawa Iesada, leaving effective administration in the hands of the Council of Elders (rōjū) led by Abe Masahiro. Abe felt that it was impossible for Japan to resist the American demands by military force and yet was reluctant to take any action on his own authority for such an unprecedented situation. Attempting to legitimize any decision taken, Abe polled all of the daimyō for their opinions. This was the first time that the Tokugawa shogunate had allowed its decision-making to be a matter of public debate and had the unforeseen consequence of portraying the shogunate as weak and indecisive. The results of the poll also failed to provide Abe with an answer; of the 61 known responses, 19 were in favour of accepting the American demands and 19 were equally opposed. Of the remainder, 14 gave vague responses expressing concern of possible war, 7 suggested making temporary concessions and 2 advised that they would simply go along with whatever was decided.

Perry returned again on February 11, 1854, with an even larger force of eight warships and made it clear that he would not be leaving until a treaty was signed. Perry continued his manipulation of the setting, such as keeping himself aloof from lower-ranking officials, implying the use of force, surveying the harbor, and refusing to meet in the designated negotiation sites. Negotiations began on March 8 and proceeded for around one month. Each party shared a performance when Perry arrived. The Americans had a technology demonstration, and the Japanese had a sumo wrestling show. While the new technology awed the Japanese people, Perry was unimpressed by the sumo wrestlers and perceived such performance as foolish and degrading: “This disgusting exhibition did not terminate until the whole twenty-five had, successively, in pairs, displayed their immense powers and savage qualities." The Japanese side gave in to almost all of Perry's demands, with the exception of a commercial agreement modelled after previous American treaties with China, which Perry agreed to defer to a later time. The main controversy centered on the selection of the ports to open, with Perry adamantly rejecting Nagasaki.

The treaty, written in English, Dutch, Chinese and Japanese, was signed on March 31, 1854, at what is now Kaikō Hiroba (Port Opening Square) Yokohama, a site adjacent to the current Yokohama Archives of History. The celebratory events for the signing ceremony included a Kabuki play from the Japanese side and, from the American side, U.S. military band music and blackface minstrelsy.

Treaty of Peace and Amity (1854)
The "Japan-US Treaty of Peace and Amity" has twelve articles:

At the time, shōgun Tokugawa Iesada was the de facto ruler of Japan; for the Emperor of Japan to interact in any way with foreigners was out of the question. Perry concluded the treaty with representatives of the shogun, led by plenipotentiary Hayashi Akira (林韑) and the text was endorsed subsequently, albeit reluctantly, by Emperor Kōmei. The treaty was ratified on February 21, 1855.

Consequences of the treaty
In the short term, the U.S. was content with the agreement since Perry had achieved his primary objective of breaking Japan's sakoku policy and setting the grounds for protection of American citizens and an eventual commercial agreement. On the other hand, the Japanese were forced into this trade, and many saw it as a sign of weakness. The Tokugawa shogunate could point out that the treaty was not actually signed by the shogun, or indeed any of his rōjū, and that it had at least temporarily averted the possibility of immediate military confrontation.

Externally, the treaty led to the United States-Japan Treaty of Amity and Commerce, the "Harris Treaty" of 1858, which allowed the establishment of foreign concessions, extraterritoriality for foreigners, and minimal import taxes for foreign goods. The Japanese chafed under the "unequal treaty system" which characterized Asian and western relations during this period. The Kanagawa treaty was also followed by similar agreements with the United Kingdom (Anglo-Japanese Friendship Treaty, October 1854), Russia (Treaty of Shimoda, February 7, 1855), and France (Treaty of Amity and Commerce between France and Japan, October 9, 1858).

Internally, the treaty had far-reaching consequences. Decisions to suspend previous restrictions on military activities led to re-armament by many domains and further weakened the position of the shogun. Debate over foreign policy and popular outrage over perceived appeasement to the foreign powers was a catalyst for the sonnō jōi movement and a shift in political power from Edo back to the Imperial Court in Kyoto. The opposition of Emperor Kōmei to the treaties further lent support to the tōbaku (overthrow the shogunate) movement, and eventually to the Meiji Restoration, which affected all realms of Japanese life. Following this period came an increase in foreign trade, the rise of Japanese military might, and the later rise of Japanese economic and technological advancement. Westernization at the time was a defense mechanism, but Japan has since found a balance between Western modernity and Japanese tradition.

title: Convention of Kanagawa


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Canis Major

Canis Major is a constellation in the southern celestial hemisphere. In the second century, it was included in Ptolemy's 48 constellations, and is counted among the 88 modern constellations. Its name is Latin for "greater dog" in contrast to Canis Minor, the "lesser dog"; both figures are commonly represented as following the constellation of Orion the hunter through the sky. The Milky Way passes through Canis Major and several open clusters lie within its borders, most notably M41.

Canis Major contains Sirius, the brightest star in the night sky, known as the "dog star". It is bright because of its proximity to the Solar System and its intrinsic brightness. In contrast, the other bright stars of the constellation are stars of great distance and high luminosity. At magnitude 1.5, Epsilon Canis Majoris (Adhara) is the second-brightest star of the constellation and the brightest source of extreme ultraviolet radiation in the night sky. Next in brightness are the yellow-white supergiant Delta (Wezen) at 1.8, the blue-white giant Beta (Mirzam) at 2.0, blue-white supergiants Eta (Aludra) at 2.4 and Omicron2 at 3.0, and white spectroscopic binary Zeta (Furud), also at 3.0. The red hypergiant VY CMa is one of the largest stars known, while the neutron star RX J0720.4-3125 has a radius of a mere 5 km.

In western astronomy
In ancient Mesopotamia, Sirius, named KAK.SI.SA2 by the Babylonians, was seen as an arrow aiming towards Orion, while the southern stars of Canis Major and a part of Puppis were viewed as a bow, named BAN in the Three Stars Each tablets, dating to around 1100 BC. In the later compendium of Babylonian astronomy and astrology titled MUL.APIN, the arrow, Sirius, was also linked with the warrior Ninurta, and the bow with Ishtar, daughter of Enlil. Ninurta was linked to the later deity Marduk, who was said to have slain the ocean goddess Tiamat with a great bow, and worshipped as the principal deity in Babylon. The Ancient Greeks replaced the bow and arrow depiction with that of a dog. In Greek Mythology, Canis Major represented the dog Laelaps, a gift from Zeus to Europa; or sometimes the hound of Procris, Diana's nymph; or the one given by Aurora to Cephalus, so famed for its speed that Zeus elevated it to the sky. It was also considered to represent one of Orion's hunting dogs, pursuing Lepus the Hare or helping Orion fight Taurus the Bull; and is referred to in this way by Aratos, Homer and Hesiod. The ancient Greeks refer only to one dog, but by Roman times, Canis Minor appears as Orion's second dog. Alternative names include Canis Sequens and Canis Alter. Canis Syrius was the name used in the 1521 Alfonsine tables.

The Roman myth refers to Canis Major as Custos Europae, the dog guarding Europa but failing to prevent her abduction by Jupiter in the form of a bull, and as Janitor Lethaeus, "the watchdog". In medieval Arab astronomy, the constellation became al-Kalb al-Akbar, "the Greater Dog", transcribed as Alcheleb Alachbar by 17th century writer Edmund Chilmead. Islamic scholar Abū Rayḥān al-Bīrūnī referred to Orion as Kalb al-Jabbār, "the Dog of the Giant". Among the Merazig of Tunisia, shepherds note six constellations that mark the passage of the dry, hot season. One of them, called Merzem, includes the stars of Canis Major and Canis Minor and is the herald of two weeks of hot weather.

In non-western astronomy

In Chinese astronomy, the modern constellation of Canis Major is located in the Vermilion Bird, where the stars were classified in several separate asterisms of stars. The Military Market was a circular pattern of stars containing Nu3, Beta, Xi1 and Xi2, and some stars from Lepus. The Wild Cockerel was at the centre of the Military Market, although it is uncertain which stars depicted what. Schlegel reported that the stars Omicron and Pi Canis Majoris might have been them, while Beta or Nu2 have also been proposed. Sirius was Tiānláng (天狼), the Celestial Wolf, denoting invasion and plunder. Southeast of the Wolf was the asterism Húshǐ (弧矢), the celestial Bow and Arrow, which was interpreted as containing Delta, Epsilon, Eta and Kappa Canis Majoris and Delta Velorum. Alternatively, the arrow was depicted by Omicron2 and Eta and aiming at Sirius (the Wolf), while the bow comprised Kappa, Epsilon, Sigma, Delta and 164 Canis Majoris, and Pi and Omicron Puppis.

Both the Māori people and the people of the Tuamotus recognized the figure of Canis Major as a distinct entity, though it was sometimes absorbed into other constellations. Te Huinga-o-Rehua, also called Te Putahi-nui-o-Rehua and Te Kahui-Takurua, ("The Assembly of Rehua" or "The Assembly of Sirius") was a Māori constellation that included both Canis Minor and Canis Major, along with some surrounding stars. Related was Taumata-o-Rehua, also called Pukawanui, the Mirror of Rehua, formed from an undefined group of stars in Canis Major. They called Sirius Rehua and Takarua, corresponding to two of the names for the constellation, though Rehua was a name applied to other stars in various Māori groups and other Polynesian cosmologies. The Tuamotu people called Canis Major Muihanga-hetika-o-Takurua, "the abiding assemblage of Takarua".

The Tharumba people of the Shoalhaven River saw three stars of Canis Major as Wunbula (Bat) and his two wives Murrumbool (Mrs Brown Snake) and Moodtha (Mrs Black Snake); bored of following their husband around, the women try to bury him while he is hunting a wombat down its hole. He spears them and all three are placed in the sky as the constellation Munowra. To the Boorong people of Victoria, Sigma Canis Majoris was Unurgunite (which has become the official name of this star ), and its flanking stars Delta and Epsilon were his two wives. The moon (Mityan, "native cat") sought to lure the further wife (Epsilon) away, but Unurgunite assaulted him and he has been wandering the sky ever since.

Characteristics
Canis Major is a constellation in the Southern Hemisphere's summer (or northern hemisphere's winter) sky, bordered by Monoceros (which lies between it and Canis Minor) to the north, Puppis to the east and southeast, Columba to the southwest, and Lepus to the west. The three-letter abbreviation for the constellation, as adopted by the International Astronomical Union in 1922, is "CMa". The official constellation boundaries, as set by Belgian astronomer Eugène Delporte in 1930, are defined by a quadrilateral; in the equatorial coordinate system, the right ascension coordinates of these borders lie between 06:12.5:0 and 07:27.5:0, while the declination coordinates are between −11.03° and −33.25°. Covering 380 square degrees or 0.921% of the sky, it ranks 43rd of the 88 currently-recognized constellations in size.

Stars
Canis Major is a prominent constellation because of its many bright stars. These include Sirius (Alpha Canis Majoris), the brightest star in the night sky, as well as three other stars above magnitude 2.0. Furthermore, two other stars are thought to have previously outshone all others in the night sky—Adhara (Epsilon Canis Majoris) shone at −3.99 around 4.7 million years ago, and Mirzam (Beta Canis Majoris) peaked at −3.65 around 4.42 million years ago. Another, NR Canis Majoris, will be brightest at magnitude −0.88 in about 2.87 million years' time.

The German cartographer Johann Bayer used the Greek letters Alpha through Omicron to label the most prominent stars in the constellation, including three adjacent stars as Nu and two further pairs as Xi and Omicron, while subsequent observers designated further stars in the southern parts of the constellation that were hard to discern from Central Europe. Bayer's countryman Johann Elert Bode later added Sigma, Tau and Omega; the French astronomer Nicolas Louis de Lacaille added lettered stars a to k (though none are in use today). John Flamsteed numbered 31 stars, with 3 Canis Majoris being placed by Lacaille into Columba as Delta Columbae (Flamsteed had not recognised Columba as a distinct constellation). He also labelled two stars—his 10 and 13 Canis Majoris—as Kappa1 and Kappa2 respectively, but subsequent cartographers such as Francis Baily and John Bevis dropped the fainter former star, leaving Kappa2 as the sole Kappa. Flamsteed's listing of Nu1, Nu2, Nu3, Xi1, Xi2, Omicron1 and Omicron2 have all remained in use. Sirius is the brightest star in the night sky at apparent magnitude −1.46 and one of the closest stars to Earth at a distance of 8.6 light-years. Its name comes from the Greek word for "scorching" or "searing". Sirius is also a binary star; its companion Sirius B is a white dwarf with a magnitude of 8.4–10,000 times fainter than Sirius A to observers on Earth. The two orbit each other every 50 years. Their closest approach last occurred in 1993 and they will be at their greatest separation between 2020 and 2025. Sirius was the basis for the ancient Egyptian calendar. The star marked the Great Dog's mouth on Bayer's star atlas.

Flanking Sirius are Beta and Gamma Canis Majoris. Also called Mirzam or Murzim, Beta is a blue-white Beta Cephei variable star of magnitude 2.0, which varies by a few hundredths of a magnitude over a period of six hours. Mirzam is 500 light-years from Earth, and its traditional name means "the announcer", referring to its position as the "announcer" of Sirius, as it rises a few minutes before Sirius does. Gamma, also known as Muliphein, is a fainter star of magnitude 4.12, in reality a blue-white bright giant of spectral type B8IIe located 441 light-years from earth. Iota Canis Majoris, lying between Sirius and Gamma, is another star that has been classified as a Beta Cephei variable, varying from magnitude 4.36 to 4.40 over a period of 1.92 hours. It is a remote blue-white supergiant star of spectral type B3Ib, around 46,000 times as luminous as the sun and, at 2500 light-years distant, 300 times further away than Sirius.

Epsilon, Omicron2, Delta, and Eta Canis Majoris were called Al Adzari "the virgins" in medieval Arabic tradition. Marking the dog's right thigh on Bayer's atlas is Epsilon Canis Majoris, also known as Adhara. At magnitude 1.5, it is the second-brightest star in Canis Major and the 23rd-brightest star in the sky. It is a blue-white supergiant of spectral type B2Iab, around 404 light-years from Earth. This star is one of the brightest known extreme ultraviolet sources in the sky. It is a binary star; the secondary is of magnitude 7.4. Its traditional name means "the virgins", having been transferred from the group of stars to Epsilon alone. Nearby is Delta Canis Majoris, also called Wezen. It is a yellow-white supergiant of spectral type F8Iab and magnitude 1.84, around 1605 light-years from Earth. With a traditional name meaning "the weight", Wezen is 17 times as massive and 50,000 times as luminous as the Sun. If located in the centre of the Solar System, it would extend out to Earth as its diameter is 200 times that of the Sun. Only around 10 million years old, Wezen has stopped fusing hydrogen in its core. Its outer envelope is beginning to expand and cool, and in the next 100,000 years it will become a red supergiant as its core fuses heavier and heavier elements. Once it has a core of iron, it will collapse and explode as a supernova. Nestled between Adhara and Wezen lies Sigma Canis Majoris, known as Unurgunite to the Boorong and Wotjobaluk people, a red supergiant of spectral type K7Ib that varies irregularly between magnitudes 3.43 and 3.51.

Also called Aludra, Eta Canis Majoris is a blue-white supergiant of spectral type B5Ia with a luminosity 176,000 times and diameter around 80 times that of the Sun. Classified as an Alpha Cygni type variable star, Aludra varies in brightness from magnitude 2.38 to 2.48 over a period of 4.7 days. It is located 1120 light-years away. To the west of Adhara lies 3.0-magnitude Zeta Canis Majoris or Furud, around 362 light-years distant from Earth. It is a spectroscopic binary, whose components orbit each other every 1.85 years, the combined spectrum indicating a main star of spectral type B2.5V.

Between these stars and Sirius lie Omicron1, Omicron2, and Pi Canis Majoris. Omicron2 is a massive supergiant star about 21 times as massive as the Sun. Only 7 million years old, it has exhausted the supply of hydrogen at its core and is now processing helium. It is an Alpha Cygni variable that undergoes periodic non-radial pulsations, which cause its brightness to cycle from magnitude 2.93 to 3.08 over a 24.44-day interval. Omicron1 is an orange K-type supergiant of spectral type K2.5Iab that is an irregular variable star, varying between apparent magnitudes 3.78 and 3.99. Around 18 times as massive as the Sun, it shines with 65,000 times its luminosity.

North of Sirius lie Theta and Mu Canis Majoris, Theta being the most northerly star with a Bayer designation in the constellation. Around 8 billion years old, it is an orange giant of spectral type K4III that is around as massive as the Sun but has expanded to 30 times the Sun's diameter. Mu is a multiple star system located around 1244 light-years distant, its components discernible in a small telescope as a 5.3-magnitude yellow-hued and 7.1-magnitude bluish star. The brighter star is a giant of spectral type K2III, while the companion is a main sequence star of spectral type B9.5V. Nu1 Canis Majoris is a yellow-hued giant star of magnitude 5.7, 278 light-years away; it is at the threshold of naked-eye visibility. It has a companion of magnitude 8.1.

At the southern limits of the constellation lie Kappa and Lambda Canis Majoris. Although of similar spectra and nearby each other as viewed from Earth, they are unrelated. Kappa is a Gamma Cassiopeiae variable of spectral type B2Vne, which brightened by 50% between 1963 and 1978, from magnitude 3.96 or so to 3.52. It is around 659 light-years distant. Lambda is a blue-white B-type main sequence dwarf with an apparent magnitude of 4.48 located around 423 light-years from Earth. It is 3.7 times as wide as and 5.5 times as massive as the Sun, and shines with 940 times its luminosity.

Canis Major is also home to many variable stars. EZ Canis Majoris is a Wolf–Rayet star of spectral type WN4 that varies between magnitudes 6.71 and 6.95 over a period of 3.766 days; the cause of its variability is unknown but thought to be related to its stellar wind and rotation. VY Canis Majoris is a remote red hypergiant located approximately 3,800 light-years away from Earth. It is one of largest stars known (sometimes described as the largest known) and is also one of the most luminous with a radius varying from 1,420 to 2,200 times the Sun's radius, and a luminosity around 300,000 times greater than the Sun. Its current mass is about 17 ± 8 solar masses, having shed material from an initial mass of 25–32 solar masses. VY CMa is also surrounded by a red reflection nebula that has been made by the material expelled by the strong stellar winds of its central star. W Canis Majoris is a type of red giant known as a carbon star—a semiregular variable, it ranges between magnitudes 6.27 and 7.09 over a period of 160 days. A cool star, it has a surface temperature of around 2,900 K and a radius 234 times that of the Sun, its distance estimated at 1,444–1,450 light-years from Earth. At the other extreme in size is RX J0720.4-3125, a neutron star with a radius of around 5 km. Exceedingly faint, it has an apparent magnitude of 26.6. Its spectrum and temperature appear to be mysteriously changing over several years. The nature of the changes are unclear, but it is possible they were caused by an event such as the star's absorption of an accretion disc.

Tau Canis Majoris is a Beta Lyrae-type eclipsing multiple star system that varies from magnitude 4.32 to 4.37 over 1.28 days. Its four main component stars are hot O-type stars, with a combined mass 80 times that of the Sun and shining with 500,000 times its luminosity, but little is known of their individual properties. A fifth component, a magnitude 10 star, lies at a distance of 13000 AU. The system is only 5 million years old. UW Canis Majoris is another Beta Lyrae-type star 3000 light-years from Earth; it is an eclipsing binary that ranges in magnitude from a minimum of 5.3 to a maximum of 4.8. It has a period of 4.4 days; its components are two massive hot blue stars, one a blue supergiant of spectral type O7.5–8 Iab, while its companion is a slightly cooler, less evolved and less luminous supergiant of spectral type O9.7Ib. The stars are 200,000 and 63,000 times as luminous as the Sun. However the fainter star is the more massive at 19 solar masses to the primary's 16. R Canis Majoris is another eclipsing binary that varies from magnitude 5.7 to 6.34 over 1.13 days, with a third star orbiting these two every 93 years. The shortness of the orbital period and the low ratio between the two main components make this an unusual Algol-type system.

Seven star systems have been found to have planets. Nu2 Canis Majoris is an ageing orange giant of spectral type K1III of apparent magnitude 3.91 located around 64 light-years distant. Around 1.5 times as massive and 11 times as luminous as the Sun, it is orbited over a period of 763 days by a planet 2.6 times as massive as Jupiter. HD 47536 is likewise an ageing orange giant found to have a planetary system—echoing the fate of the Solar System in a few billion years as the Sun ages and becomes a giant. Conversely, HD 45364 is a star 107 light-years distant that is a little smaller and cooler than the Sun, of spectral type G8V, which has two planets discovered in 2008. With orbital periods of 228 and 342 days, the planets have a 3:2 orbital resonance, which helps stabilise the system. HD 47186 is another sunlike star with two planets; the inner—HD 47186 b—takes four days to complete an orbit and has been classified as a Hot Neptune, while the outer—HD 47186 c—has an eccentric 3.7-year period orbit and has a similar mass to Saturn. HD 43197 is a sunlike star around 183 light-years distant that has two planets: a hot Jupiter-size planet with an eccentric orbit. The other planet, HD 43197 c, is another massive Jovian planet with a slightly oblong orbit outside of its habitable zone.

Z Canis Majoris is a star system a mere 300,000 years old composed of two pre-main-sequence stars—a FU Orionis star and a Herbig Ae/Be star, which has brightened episodically by two magnitudes to magnitude 8 in 1987, 2000, 2004 and 2008. The more massive Herbig Ae/Be star is enveloped in an irregular roughly spherical cocoon of dust that has an inner diameter of 20 AU and outer diameter of 50 AU. The cocoon has a hole in it through which light shines that covers an angle of 5 to 10 degrees of its circumference. Both stars are surrounded by a large envelope of in-falling material left over from the original cloud that formed the system. Both stars are emitting jets of material, that of the Herbig Ae/Be star being much larger—11.7 light-years long. Meanwhile, FS Canis Majoris is another star with infra-red emissions indicating a compact shell of dust, but it appears to be a main-sequence star that has absorbed material from a companion. These stars are thought to be significant contributors to interstellar dust.

Deep-sky objects
The band of the Milky Way goes through Canis Major, with only patchy obscurement by interstellar dust clouds. It is bright in the northeastern corner of the constellation, as well as in a triangular area between Adhara, Wezen and Aludra, with many stars visible in binoculars. Canis Major boasts several open clusters. The only Messier object is M41 (NGC 2287), an open cluster with a combined visual magnitude of 4.5, around 2300 light-years from Earth. Located 4 degrees south of Sirius, it contains contrasting blue, yellow and orange stars and covers an area the apparent size of the full moon—in reality around 25 light-years in diameter. Its most luminous stars have already evolved into giants. The brightest is a 6.3-magnitude star of spectral type K3. Located in the field is 12 Canis Majoris, though this star is only 670 light-years distant. NGC 2360, known as Caroline's Cluster after its discoverer Caroline Herschel, is an open cluster located 3.5 degrees west of Muliphein and has a combined apparent magnitude of 7.2. Around 15 light-years in diameter, it is located 3700 light-years away from Earth, and has been dated to around 2.2 billion years old. NGC 2362 is a small, compact open cluster, 5200 light-years from Earth. It contains about 60 stars, of which Tau Canis Majoris is the brightest member. Located around 3 degrees northeast of Wezen, it covers an area around 12 light-years in diameter, though the stars appear huddled around Tau when seen through binoculars. It is a very young open cluster as its member stars are only a few million years old. Lying 2 degrees southwest of NGC 2362 is NGC 2354 a fainter open cluster of magnitude 6.5, with around 15 member stars visible with binoculars. Located around 30' northeast of NGC 2360, NGC 2359 (Thor's Helmet or the Duck Nebula) is a relatively bright emission nebula in Canis Major, with an approximate magnitude of 10, which is 10,000 light-years from Earth. The nebula is shaped by HD 56925, an unstable Wolf–Rayet star embedded within it.

In 2003, an overdensity of stars in the region was announced to be the Canis Major Dwarf, the closest satellite galaxy to Earth. However, there remains debate over whether it represents a disrupted dwarf galaxy or in fact a variation in the thin and thick disk and spiral arm populations of the Milky Way. Investigation of the area yielded only ten RR Lyrae variables—consistent with the Milky Way's halo and thick disk populations rather than a separate dwarf spheroidal galaxy. On the other hand, a globular cluster in Puppis, NGC 2298—which appears to be part of the Canis Major dwarf system—is extremely metal-poor, suggesting it did not arise from the Milky Way's thick disk, and instead is of extragalactic origin.

NGC 2207 and IC 2163 are a pair of face-on interacting spiral galaxies located 125 million light-years from Earth. About 40 million years ago, the two galaxies had a close encounter and are now moving farther apart; nevertheless, the smaller IC 2163 will eventually be incorporated into NGC 2207. As the interaction continues, gas and dust will be perturbed, sparking extensive star formation in both galaxies. Supernovae have been observed in NGC 2207 in 1975 (type Ia SN 1975a), 1999 (the type Ib SN 1999ec), 2003 (type 1b supernova SN 2003H), and 2013 (type II supernova SN 2013ai). Located 16 million light-years distant, ESO 489-056 is an irregular dwarf- and low-surface-brightness galaxy that has one of the lowest metallicities known.

title: Canis Major


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Canis Minor

Canis Minor is a small constellation in the northern celestial hemisphere. In the second century, it was included as an asterism, or pattern, of two stars in Ptolemy's 48 constellations, and it is counted among the 88 modern constellations. Its name is Latin for "lesser dog", in contrast to Canis Major, the "greater dog"; both figures are commonly represented as following the constellation of Orion the hunter.

Canis Minor contains only two stars brighter than the fourth magnitude, Procyon (Alpha Canis Minoris), with a magnitude of 0.34, and Gomeisa (Beta Canis Minoris), with a magnitude of 2.9. The constellation's dimmer stars were noted by Johann Bayer, who named eight stars including Alpha and Beta, and John Flamsteed, who numbered fourteen. Procyon is the eighth-brightest star in the night sky, as well as one of the closest. A yellow-white main-sequence star, it has a white dwarf companion. Gomeisa is a blue-white main-sequence star. Luyten's Star is a ninth-magnitude red dwarf and the Solar System's next closest stellar neighbour in the constellation after Procyon. Additionally, Procyon and Luyten's Star are only 1.12 light-years away from each other, and Procyon would be the brightest star in Luyten's Star's sky. The fourth-magnitude HD 66141, which has evolved into an orange giant towards the end of its life cycle, was discovered to have a planet in 2012. There are two faint deep-sky objects within the constellation's borders. The 11 Canis-Minorids are a meteor shower that can be seen in early December.

History and mythology
Though strongly associated with the Classical Greek uranographic tradition, Canis Minor originates from ancient Mesopotamia. Procyon and Gomeisa were called MASH.TAB.BA or "twins" in the Three Stars Each tablets, dating to around 1100 BC. In the later MUL.APIN, this name was also applied to the pairs of Pi3 and Pi4 Orionis and Zeta and Xi Orionis. The meaning of MASH.TAB.BA evolved as well, becoming the twin deities Lulal and Latarak, who are on the opposite side of the sky from Papsukkal, the True Shepherd of Heaven in Babylonian mythology. Canis Minor was also given the name DAR.LUGAL, its position defined as "the star which stands behind it [Orion]", in the MUL.APIN; the constellation represents a rooster. This name may have also referred to the constellation Lepus. DAR.LUGAL was also denoted DAR.MUŠEN and DAR.LUGAL.MUŠEN in Babylonia. Canis Minor was then called tarlugallu in Akkadian astronomy.

Canis Minor was one of the original 48 constellations formulated by Ptolemy in his second-century Almagest, in which it was defined as a specific pattern (asterism) of stars; Ptolemy identified only two stars and hence no depiction was possible. The Ancient Greeks called the constellation προκυων/Procyon, "coming before the dog", transliterated into Latin as Antecanis, Praecanis, or variations thereof, by Cicero and others. Roman writers also appended the descriptors parvus, minor or minusculus ("small" or "lesser", for its faintness), septentrionalis ("northerly", for its position in relation to Canis Major), primus (rising "first") or sinister (rising to the "left") to its name Canis. In Greek mythology, Canis Minor was sometimes connected with the Teumessian Fox, a beast turned into stone with its hunter, Laelaps, by Zeus, who placed them in heaven as Canis Major (Laelaps) and Canis Minor (Teumessian Fox). Eratosthenes accompanied the Little Dog with Orion, while Hyginus linked the constellation with Maera, a dog owned by Icarius of Athens. On discovering the latter's death, the dog and Icarius' daughter Erigone took their lives and all three were placed in the sky—Erigone as Virgo and Icarius as Boötes. As a reward for his faithfulness, the dog was placed along the "banks" of the Milky Way, which the ancients believed to be a heavenly river, where he would never suffer from thirst.

The medieval Arabic astronomers maintained the depiction of Canis Minor (al-Kalb al-Asghar in Arabic) as a dog; in his Book of the Fixed Stars, Abd al-Rahman al-Sufi included a diagram of the constellation with a canine figure superimposed. There was one slight difference between the Ptolemaic vision of Canis Minor and the Arabic; al-Sufi claims Mirzam, now assigned to Orion, as part of both Canis Minor—the collar of the dog—and its modern home. The Arabic names for both Procyon and Gomeisa alluded to their proximity and resemblance to Sirius, though they were not direct translations of the Greek; Procyon was called ash-Shi'ra ash-Shamiya, the "Syrian Sirius" and Gomeisa was called ash-Shira al-Ghamisa, the Sirius with bleary eyes. Among the Merazig of Tunisia, shepherds note six constellations that mark the passage of the dry, hot season. One of them, called Merzem, includes the stars of Canis Minor and Canis Major and is the herald of two weeks of hot weather.

The ancient Egyptians thought of this constellation as Anubis, the jackal god. Alternative names have been proposed: Johann Bayer in the early 17th century termed the constellation Fovea "The Pit", and Morus "Sycamine Tree". Seventeenth-century German poet and author Philippus Caesius linked it to the dog of Tobias from the Apocrypha. Richard A. Proctor gave the constellation the name Felis "the Cat" in 1870 (contrasting with Canis Major, which he had abbreviated to Canis "the Dog"), explaining that he sought to shorten the constellation names to make them more manageable on celestial charts. Occasionally, Canis Minor is confused with Canis Major and given the name Canis Orionis ("Orion's Dog").

In non-Western astronomy
In Chinese astronomy, the stars corresponding to Canis Minor lie in the Vermilion Bird of the South (南方朱雀, Nán Fāng Zhū Què). Procyon, Gomeisa and Eta Canis Minoris form an asterism known as Nánhé, the Southern River. With its counterpart, the Northern River Beihe (Castor and Pollux), Nánhé was also associated with a gate or sentry. Along with Zeta and 8 Cancri, 6 Canis Minoris and 11 Canis Minoris formed the asterism Shuiwei, which literally means "water level". Combined with additional stars in Gemini, Shuiwei represented an official who managed floodwaters or a marker of the water level. Neighboring Korea recognized four stars in Canis Minor as part of a different constellation, "the position of the water". This constellation was located in the Red Bird, the southern portion of the sky.

Polynesian peoples often did not recognize Canis Minor as a constellation, but they saw Procyon as significant and often named it; in the Tuamotu Archipelago it was known as Hiro, meaning "twist as a thread of coconut fiber", and Kopu-nui-o-Hiro ("great paunch of Hiro"), which was either a name for the modern figure of Canis Minor or an alternative name for Procyon. Other names included Vena (after a goddess), on Mangaia and Puanga-hori (false Puanga, the name for Rigel), in New Zealand. In the Society Islands, Procyon was called Ana-tahua-vahine-o-toa-te-manava, literally "Aster the priestess of brave heart", figuratively the "pillar for elocution". The Wardaman people of the Northern Territory in Australia gave Procyon and Gomeisa the names Magum and Gurumana, describing them as humans who were transformed into gum trees in the dreamtime. Although their skin had turned to bark, they were able to speak with a human voice by rustling their leaves.

The Aztec calendar was related to their cosmology. The stars of Canis Minor were incorporated along with some stars of Orion and Gemini into an asterism associated with the day called "Water".

Characteristics
Lying directly south of Gemini's bright stars Castor and Pollux, Canis Minor is a small constellation bordered by Monoceros to the south, Gemini to the north, Cancer to the northeast, and Hydra to the east. It does not border Canis Major; Monoceros is in between the two. Covering 183 square degrees, Canis Minor ranks seventy-first of the 88 constellations in size. It appears prominently in the southern sky during the Northern Hemisphere's winter. The constellation boundaries, as set by Belgian astronomer Eugène Delporte in 1930, are defined by a polygon of 14 sides. In the equatorial coordinate system, the right ascension coordinates of these borders lie between 07:06.4:0 and 08:11.4:0, while the declination coordinates are between 13.22° and −0.36°. Most visible in the evening sky from January to March, Canis Minor is most prominent at 10 p.m. during mid-February. It is then seen earlier in the evening until July, when it is only visible after sunset before setting itself, and rising in the morning sky before dawn. The constellation's three-letter abbreviation, as adopted by the International Astronomical Union in 1922, is "CMi".

Stars

Canis Minor contains only two stars brighter than fourth magnitude. At magnitude 0.34, Procyon, or Alpha Canis Minoris, is the eighth-brightest star in the night sky, as well as one of the closest. Its name means "before the dog" or "preceding the dog" in Greek, as it rises an hour before the "Dog Star", Sirius, of Canis Major. It is a binary star system, consisting of a yellow-white main-sequence star of spectral type F5 IV-V, named Procyon A, and a faint white dwarf companion of spectral type DA, named Procyon B. Procyon B, which orbits the more massive star every 41 years, is of magnitude 10.7. Procyon A is 1.4 times the Sun's mass, while its smaller companion is 0.6 times as massive as the Sun. The system is 11.4 ly from Earth, the shortest distance to a northern-hemisphere star of the first magnitude. Gomeisa, or Beta Canis Minoris, with a magnitude of 2.89, is the second-brightest star in Canis Minor. Lying 160 ± 10 ly from the Solar System, it is a blue-white main-sequence star of spectral class B8 Ve. Although fainter to Earth observers, it is much brighter than Procyon, and is 250 times as luminous and three times as massive as the Sun. Although its variations are slight, Gomeisa is classified as a shell star (Gamma Cassiopeiae variable), with a maximum magnitude of 2.84 and a minimum magnitude of 2.92. It is surrounded by a disk of gas which it heats and causes to emit radiation.

Johann Bayer used the Greek letters Alpha to Eta to label the most prominent eight stars in the constellation, designating two stars as Delta (named Delta1 and Delta2). John Flamsteed numbered fourteen stars, discerning a third star he named Delta3; his star 12 Canis Minoris was not found subsequently. In Bayer's 1603 work Uranometria, Procyon is located on the dog's belly, and Gomeisa on its neck. Gamma, Epsilon and Eta Canis Minoris lie nearby, marking the dog's neck, crown and chest, respectively. Although it has an apparent magnitude of 4.34, Gamma Canis Minoris is an orange K-type giant of spectral class K3-III C, which lies 318 ly away. Its colour is obvious when seen through binoculars. It is a multiple system, consisting of the spectroscopic binary Gamma A and three optical companions, Gamma B, magnitude 13; Gamma C, magnitude 12; and Gamma D, magnitude 10. The two components of Gamma A orbit each other every 389.2 days, with an eccentric orbit that takes their separation between 2.3 and 1.4 astronomical units (AU). Epsilon Canis Minoris is a yellow bright giant of spectral class G6.5IIb of magnitude of 4.99. It lies 730 - 810 ly from Earth, with 13 times the diameter and 750 times the luminosity of the Sun. Eta Canis Minoris is a giant of spectral class F0III of magnitude 5.24, which has a yellowish hue when viewed through binoculars as well as a faint companion of magnitude 11.1. Located 4 arcseconds from the primary, the companion star is actually around 440 AU from the main star and takes around 5,000 years to orbit it.

Near Procyon, three stars share the name Delta Canis Minoris. Delta1 is a yellow-white F-type giant of magnitude 5.25 located around 790 ly from Earth. About 360 times as luminous and 3.75 times as massive as the Sun, it is expanding and cooling as it ages, having spent much of its life as a main sequence star of spectrum B6V. Also known as 8 Canis Minoris, Delta2 is an F-type main-sequence star of spectral type F2V and magnitude 5.59 which is 136 ly distant. The last of the trio, Delta3 (also known as 9 Canis Minoris), is a white main sequence star of spectral type A0Vnn and magnitude 5.83 which is 680 ly distant. These stars mark the paws of the Lesser Dog's left hind leg, while magnitude 5.13 Zeta marks the right. A blue-white bright giant of spectral type B8II, Zeta lies around 623 ly away from the Solar System.

Lying 222 ± 7 light-years away with an apparent magnitude of 4.39, HD 66141 is 6.8 billion years old and has evolved into an orange giant of spectral type K2III with a diameter around 22 times that of the Sun, and weighing 1.1 solar masses. It is 174 times as luminous as the Sun, with an absolute magnitude of −0.15. HD 66141 was mistakenly named 13 Puppis, as its celestial coordinates were recorded incorrectly when catalogued and hence mistakenly thought to be in the constellation of Puppis; Bode gave it the name Lambda Canis Minoris, which is now obsolete. The orange giant is orbited by a planet, HD 66141b, which was detected in 2012 by measuring the star's radial velocity. The planet has a mass around 6 times that of Jupiter and a period of 480 days.

A red giant of spectral type M4III, BC Canis Minoris lies around 500 ly distant from the Solar System. It is a semiregular variable star that varies between a maximum magnitude of 6.14 and minimum magnitude of 6.42. Periods of 27.7, 143.3 and 208.3 days have been recorded in its pulsations. AZ, AD and BI Canis Minoris are Delta Scuti variables—short period (six hours at most) pulsating stars that have been used as standard candles and as subjects to study astroseismology. AZ is of spectral type A5IV, and ranges between magnitudes 6.44 and 6.51 over a period of 2.3 hours. AD has a spectral type of F2III, and has a maximum magnitude of 9.21 and minimum of 9.51, with a period of approximately 2.95 hours. BI is of spectral type F2 with an apparent magnitude varying around 9.19 and a period of approximately 2.91 hours.

At least three red giants are Mira variables in Canis Minor. S Canis Minoris, of spectral type M7e, is the brightest, ranging from magnitude 6.6 to 13.2 over a period of 332.94 days. V Canis Minoris ranges from magnitude 7.4 to 15.1 over a period of 366.1 days. Similar in magnitude is R Canis Minoris, which has a maximum of 7.3, but a significantly brighter minimum of 11.6. An S-type star, it has a period of 337.8 days.

YZ Canis Minoris is a red dwarf of spectral type M4.5V and magnitude 11.2, roughly three times the size of Jupiter and 20 ly from Earth. It is a flare star, emitting unpredictable outbursts of energy for mere minutes, which might be much more powerful analogues of solar flares. Luyten's Star (GJ 273) is a red dwarf star of spectral type M3.5V and close neighbour of the Solar System. Its visual magnitude of 9.9 renders it too faint to be seen with the naked eye, even though it is only 12.39 ly away. Fainter still is PSS 544-7, an eighteenth-magnitude red dwarf around 20 per cent the mass of the Sun, located 685 ly from Earth. First noticed in 1991, it is thought to be a cannonball star, shot out of a star cluster and now moving rapidly through space directly away from the galactic disc.

The WZ Sagittae-type dwarf nova DY Canis Minoris (also known as VSX J074727.6+065050) flared up to magnitude 11.4 over January and February 2008 before dropping eight magnitudes to around 19.5 over approximately 80 days. It is a remote binary star system where a white dwarf and low-mass star orbit each other close enough for the former star to draw material off the latter and form an accretion disc. This material builds up until it erupts dramatically.

Deep-sky objects

The Milky Way passes through much of Canis Minor, yet it has few deep-sky objects. William Herschel recorded four objects in his 1786 work Catalogue of Nebulae and Clusters of Stars, including two he mistakenly believed were star clusters. NGC 2459 is a group of five thirteenth- and fourteenth-magnitude stars that appear to lie close together in the sky but are not related. A similar situation has occurred with NGC 2394, also in Canis Minor. This is a collection of fifteen unrelated stars of ninth magnitude and fainter.

Herschel also observed three faint galaxies, two of which are interacting with each other. NGC 2508 is a lenticular galaxy of thirteenth magnitude, estimated at 205 million light-years' distance (63 million parsecs) with a diameter of 80000 ly. Named as a single object by Herschel, NGC 2402 is actually a pair of near-adjacent galaxies that appear to be interacting with each other. Only of fourteenth and fifteenth magnitudes, respectively, the elliptical and spiral galaxy are thought to be approximately 245 million light-years distant, and each measure 55,000 light-years in diameter.

Meteor showers
The 11 Canis-Minorids, also called the Beta Canis Minorids, are a meteor shower that arise near the fifth-magnitude star 11 Canis Minoris and were discovered in 1964 by Keith Hindley, who investigated their trajectory and proposed a common origin with the comet D/1917 F1 Mellish. However, this conclusion has been refuted subsequently as the number of orbits analysed was low and their trajectories too disparate to confirm a link. They last from 4 to 15 December, peaking over 10 and 11 December.

title: Canis Minor