Big Dipper

This article is about the asterism. For other uses, see Big Dipper (disambiguation).

The asterism of the Big Dipper (shown in this star map in green) lies within the constellation of Ursa Major.

The Big Dipper (US) or Plough (UK) is an asterism (not a constellation) of seven stars, with four defining a "bowl" or "body" and three defining a "handle" or "head", that is recognized as a distinct grouping in many cultures. These stars are the brightest of the formal constellation Ursa Major; six of them are second magnitude stars, while only Megrez (δ) is of third magnitude. The North Star (Polaris), the current northern pole star and the tip of the handle of the Little Dipper, can be located by extending an imaginary line from Merak (β) through Dubhe (α). This makes it useful in celestial navigation.

Names

The Big Dipper seen from Kauai.

The Big Dipper seen from Suffolk.

Origin

The constellation of Ursa Major has been seen as a bear by many distinct civilizations. This may stem from a common oral tradition stretching back for thousands of years. Using statistical and phylogenetic tools, Julien d'Huy reconstructs the following Palaeolithic state of the story: "There is an animal that is a horned herbivore, especially an elk. One human pursues this ungulate. The hunt locates or get to the sky. The animal is alive when it is transformed into a constellation. It forms the Big Dipper".

North America

In Canada and the United States, the asterism is known as the Big Dipper because the major stars can be seen to follow the rough outline of a large ladle or "dipper". This figuration appears to be derived originally from Africa, where it was sometimes seen as a drinking gourd.

A widespread American Indian figuration had the bowl as a bear. Some groups considered the handle to be three cubs following their mother, while others pictured three hunters tracking the bear. The Anishinaabe or Ojibway First Nation know the Big Dipper as the "Fisher Star" (Ojig-anang) after the fisher cat.

Europe

The "Starry Plough", used by Irish nationalists and leftists.

In both Ireland and the United Kingdom, this pattern is known as the Plough. The symbol of the Starry Plough has been used as a political symbol by Irish Republican and left wing movements. Another former name was the Great Wain (i.e., wagon). In northern England, it is occasionally still known as the Butcher's Cleaver, and in the northeast, as Charlie's Wagon. This derives from the earlier Charles's Wain and Charles his Wain, which derived from the still older Carlswæn. A folk etymology holds that this derived from Charlemagne, but the name is common to all the Germanic languages and intended the churls' wagon (i.e., "the men's wagon"), in contrast with the women's wagon (the Little Dipper). An older "Odin's Wain" may have preceded these Nordic designations.

The "Great Wain" seen from Berlin (2011)

In German, it is known as the "Great Wagon" (Großer Wagen) and, less often, the "Great Bear" (Großer Bär). In Scandinavia, it is known by variations of "Charles's Wagon" (Karlavagnen, Karlsvogna, or Karlsvognen). In Dutch, its official name is the "Great Bear" (Grote Beer), but it is popularly known as the "Saucepan" (Steelpannetje).

In Romanian and most Slavic languages, it is known as the "Great Wagon" but, in Hungarian, it is commonly called "Göncöl's Wagon" (Göncölszekér) or, less often, "Big Göncöl" (Nagy Göncöl) after a táltos in Hungarian mythology who carried medicine that could cure any disease. In Finnish, the figure is known as the "Salmon Net" (Otava) and widely used as a cultural symbol. The brown bear in Finnish actually became known as otava, but this is claimed to stem from its resemblance to—and mythical origin from—the asterism rather than vice versa.

Book XVIII of Homer's Iliad mentions it as "the Bear, which men also call the Wain". In Latin, these seven stars were known as the "Seven Oxen" (septentriones, from septem triōnēs). Triōnēs is a hapax legomenon, occurring only in a single passage by Varro, where he glosses it as meaning "plough oxen". The derivation is acceptable but the meaning, if Varro is right that it derives from terō ("thresh grain by rubbing"), is surely "threshing oxen": the seven stars wheel around the pole star like oxen on a threshing floor. The name is the origin of septentriōnēs the Latin word for north, from which came the adjective septentrional ("northern") in English, French, Italian, Portuguese, and Spanish.

The Big Dipper seen from Spain

Asia

The Hall of the Big Dipper in a Taoist temple, Wuhan

In traditional Chinese astronomy, which continues to be used for throughout East Asia (e.g., in astrology), these stars are generally considered to compose the Right Wall of the Purple Forbidden Enclosure which surrounds the Northern Celestial Pole, although numerous other groupings and names have been made over the centuries. Similarly, each star has a distinct name, which likewise has varied over time and depending upon the asterism being constructed. The Western asterism is now known as the "Northern Dipper" (北斗) or the "Seven Stars of the Northern Dipper" (Chinese and Japanese: 北斗七星; pinyin: Běidǒu Qīxīng; Cantonese Yale: Bak¹-dau² Cat¹-sing¹; rōmaji: Hokutō Shichisei; Korean: 북두칠성; romaja: Bukdu Chilseong; Vietnamese: Sao Bắc Đẩu). The personification of the Big Dipper itself is also known as "Doumu" (斗母) in Chinese folk religion and Taoism, and Marici in Buddhism.

In Malaysian, it is known as the "Dipper Stars" (Buruj Biduk); in Indonesian, as the "Canoe Stars" (Bintang Biduk)

In Hindu astronomy, it is referred to as the "Collection of Seven Great Sages" (Saptarshi Mandal), as each star is named after a mythical Hindu sage.

An Arabian story has the four stars of the Plough's bowl as a coffin, with the three stars in the handle as mourners, following it.

In Mongolian, it is known as the "Seven Gods" (Долоон бурхан). In Kazakh, they are known as the Jetiqaraqshi (Жетіқарақшы) and, in Kyrgyz, as the Jetigen (Жетиген).

Stars

Within Ursa Major the stars of the Big Dipper have Bayer designations in consecutive Greek alphabetical order from the bowl to the handle.

The Big Dipper's bowl and part of the handle photographed from the International Space Station.
Mizar and Alcor are at the upper right.

Proper Name	Bayer Designation	Apparent Magnitude	Distance (L Yrs)
Dubhe	α UMa	1.8	124
Merak	β UMa	2.4	79
Phecda	γ UMa	2.4	84
Megrez	δ UMa	3.3	58
Alioth	ε UMa	1.8	81
Mizar	ζ UMa	2.1	78
Alkaid	η UMa	1.9	101

In the same line of sight as Mizar, but about one light-year beyond it, is the star Alcor (80 UMa). Together they are known as the "Horse and Rider". At fourth magnitude, Alcor would normally be relatively easy to see with the unaided eye, but its proximity to Mizar renders it more difficult to resolve, and it has served as a traditional test of sight. Mizar itself has four components and thus enjoys the distinction of being part of an optical binary as well as being the first-discovered telescopic binary (1617) and the first-discovered spectroscopic binary (1889).

4D proper moving in -/+ 150 000 years. 3D red cyan glasses are recommended to view this image correctly.

Five of the stars of the Big Dipper are at the core of the Ursa Major Moving Group. The two at the ends, Dubhe and Alkaid, are not part of the swarm, and are moving in the opposite direction. Relative to the central five, they are moving down and to the right in the map. This will slowly change the Dipper's shape, with the bowl opening up and the handle becoming more bent. In 50,000 years the Dipper will no longer exist as we know it, but be re-formed into a new Dipper facing the opposite way. The stars Alkaid to Phecda will then constitute the bowl, while Phecda, Merak, and Dubhe will be the handle.

Guidepost

Not only are the stars in the Big Dipper easily found themselves, they may also be used as guides to yet other stars. Thus it is often the starting point for introducing Northern Hemisphere beginners to the night sky:

• Polaris, the North Star, is found by imagining a line from Merak (β) to Dubhe (α) and then extending it for five times the distance between the two Pointers.
• Extending a line from Megrez (δ) to Phecda (γ), on the inside of the bowl, leads to Regulus (α Leonis) and Alphard (α Hydrae). A mnemonic for this is "A hole in the bowl will leak on Leo."
• Crossing the top of the bowl from Megrez (δ) to Dubhe (α) takes one in the direction of Capella (α Aurigae). A mnemonic for this is "Cap to Capella."
• Castor (α Geminorum) is reached by imagining a diagonal line from Megrez (δ) to Merak (β) and then extending it for approximately five times that distance.
• By following the curve of the handle from Alioth (ε) to Mizar (ζ) to Alkaid (η), one reaches Arcturus (α Boötis) and Spica (α Virginis). A mnemonic for this is "Arc to Arcturus then speed (or spike) to Spica."

Additionally, the Dipper may be used as a guide to telescopic objects:

• The approximate location of the Hubble Deep Field can be found by following a line from Phecda (γ) to Megrez (δ) and continuing on for the same distance again.
• Crossing the bowl diagonally from Phecda (γ) to Dubhe (α) and proceeding onward for a similar stretch leads to the bright galaxy pair M81 and M82.
• Two spectacular spiral galaxies flank Alkaid (η), the Pinwheel (M101) to the north and the Whirlpool (M51) to the south.
• Projecting a line from Alkaid through the pole star will point to Cassiopeia.

Cultural associations

Alaska state flag.

The "Seven Stars" referenced in the Bible's Book of Amos may refer to these stars or, more likely, to the Pleiades.

The Big Dipper is used as a part of the inescutcheon in the Swedish coat of arms and on the state flag of Alaska. Among the American Indians, the Dipper appears on some tribal flags.

In the 19th century, runaway slaves in the United States would "Follow the Drinkin' Gourd" to the North and to Canada with hopes of freedom.

In Tolkien's Middle-earth mythos, it is called the Valacirca (Sickle of the Valar), the sign of Hope signifying doom for Evil, while in T.A. Barron's Great Tree of Avalon series, it is called the Wizard's Staff, symbolizing Merlin's staff.

It is a prominent symbol in the Fist of the North Star manga/anime series; Kenshiro has a set of scars on his chest inflicted by Shin that follow the Big Dipper's pattern. Most of the moves in Hokuto Shinken used by Kenshiro, Raoh, Toki and Jagi bear the asterism's name, and Kenshiro himself represents Ursa Major as a whole, being the successor to the martial art's style. Finally, the Big Dipper can often be seen in the night sky whenever Kenshiro is present in a scene.

The main human protagonist of the 1972 Tsuburaya Productions Tokusatsu TV Series Ultraman Ace is named Seiji Hokuto.

In the manga X/1999 and its anime adaptation, it serves as a major recurring theme of the series mythos.

In the video game Shin Megami Tensei: Devil Survivor 2, the seven stars of the Big Dipper (known as Septentriones) appear as the primary antagonists of the game, while Polaris serves as the game's final boss.

In the video game Uncharted 3: Drake's Deception, the player has to find the big dipper in the sky.

In the video game Monster Hunter 3, the seven stars of the Big Dipper appear as names of weapons of different classes all titled as the name of the star followed by Asterism in reference to this constellation.

The last track of Mannheim Steamroller's Fresh Aire 7 album is inspired by Chip Davis' sights of the Big Dipper when a child, and named after the constellation.

In the Yu-Gi-Oh! Zexal anime, the Seven Barian Emperors have names based on stars of Big Dipper.

In the 13th Movie of the Case Closed Anime (Detective Conan) the Big Dipper plays a vital role for the criminals actions.

In the Disney Channel's animated series Gravity Falls, the main character's nickname is Dipper, due to the Big Dipper birthmark on his forehead.

In addition to appearing on the flags of political entities, the Dipper has also been used in corporate logos.

See also

• Abenaki mythology
• Amenominakanushi
• Apkallu
• Saptarishi
• Seven Sages of Greece
• Swastika symbols
• Taidi