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Canopus (; α Car, α Carinae, Alpha Carinae) is the brightest star in the southern constellation of Carina, and the second brightest star in the night-time sky, after Sirius. Canopus's visual magnitude is −0.72, and it has an absolute magnitude of −5.65. Canopus is a supergiant of spectral type F. Canopus is essentially white when seen with the naked eye (although F-type stars are sometimes listed as "yellowish-white"). It is located in the far southern sky, at a declination of −52° 42' (2000) and a right ascension of 06h24.0m.〔 Its name comes from the mythological Canopus, who was a navigator for Menelaus, king of Sparta. ==Observational history== In Indian Vedic literature, the star Canopus is associated with the sage Agastya, one of the ancient rishis (the others are associated with the stars of the Big Dipper). Agastya, the star, is said to be the 'cleanser of waters' and its rising coincides with the calming of the waters of the Indian Ocean. It is considered the son of Pulasthya, son of Brahma. Canopus was not visible to the ancient Greeks and Romans; it was, however, visible to the ancient Egyptians,〔Schaaf, p. 107.〕 as well as the Navajo, who named it ''Ma’ii Bizò‘''.〔Maryboy, Nancy D. (2004). ''A Guide to Navajo Astronomy.'' Indigenous Education Institute : Bluff, Utah.〕 The Bedouin people of the Negev and Sinai also knew it as ''Suhayl'', and used it and Polaris as the two principal stars for navigation at night. Due to the fact that it disappears below the horizon, it became associated with a changeable nature, as opposed to always-visible Polaris, which was circumpolar and hence 'steadfast'. It is also referred to by its Arabic name: سهيل (''Suhayl'', ''Soheil'' in Persian), given by Islamic scientists in the 7th century AD. Called the Star of the Old Man (in ) in Chinese, Canopus appears (albeit misplaced northwards) on the medieval Chinese manuscript the Dunhuang star chart, despite not being visible from China. The Chinese astronomer Yi Xing had journeyed south to chart Canopus and other far southern stars in 724 AD, though they were likely known to the Chinese from earlier times.〔 Bright stars were important to the ancient Polynesians for navigation between the many islands and atolls of the Pacific Ocean. Low on the horizon, they acted as stellar compasses to assist mariners in charting courses to particular destinations. Canopus served as the southern wingtip of a "Great Bird" constellation called ''Manu'', with Sirius as the body and Procyon the northern wingtip, which divided the Polynesian night sky into two hemispheres. The Hawaiian people called Canopus ''Ke Alii-o-kona-i-ka-lewa'', "The chief of the southern expanse"; it was one of the stars used by Hawaii-loa and Ki when they traveled to the Southern Ocean. The Māori people of New Zealand/Aotearoa had several different names for Canopus. ''Ariki'' ("High-born"), was known as a solitary star that appeared in the east, prompting people to weep and chant. They also named it ''Atutahi'', ''Aotahi'' or ''Atuatahi'', "Stand Alone".〔p. 419, (''Mythology: Myths, Legends and Fantasies'' ), Janet Parker, Alice Mills, Julie Stanton, Durban, Struik Publishers, 2007.〕 Its solitary nature indicates it is a ''tapu'' star, as ''tapu'' people are often solitary. Its appearance at the beginning of the ''Maruaroa'' season foretells the coming winter; light rays to the south indicate a cold wet winter, and to the north foretell a mild winter. Food was offered to the star on its appearance. This name has several different mythologies attached to it as well. One story tells of how Atutahi was left outside of the basket representing the Milky Way when Tāne wove it. Another related myth surrounding the star says that Atutahi was the first-born child of Rangi, who refused to enter the Milky Way and so turned it sideways and rose before it. The same name is used for other stars and constellations throughout Polynesia. ''Kapae-poto'', "Short horizon", referred to the fact that it rarely sets from the vantage point of New Zealand; ''Kauanga'' ("Solitary") was the name for Canopus only when it was the last star visible before sunrise. The Tswana people of Botswana knew Canopus as ''Naka''. Appearing late in winter skies, it heralded increasing winds and a time when trees lose their leaves. Stock owners knew it was time to their sheep with rams. To the ǀXam-speaking Bushmen of South Africa, Canopus and Sirius signalled the appearance of termites and flying ants. They also believed stars had the power to cause death and misfortune, and they would pray to Sirius and Canopus in particular to impart good fortune or skill. The Kalapalo people of Mato Grosso state in Brazil saw Canopus and Procyon as ''Kofongo'' "Duck", with Castor and Pollux representing his hands. The asterism's appearance signified the coming of the rainy season and increase in manioc, a food staple fed to guests at feasts. Canopus traditionally marked the rudder of the ship Argo Navis. English explorer Robert Hues brought it to the attention of European observers in his 1592 work ''Tractatus de Globis'', along with Achernar and Alpha Centauri, noting "Now, therefore, there are but three Stars of the first magnitude that I could perceive in all those parts which are never seene here in England. The first of these is that bright Star in the sterne of Argo which they call Canobus. The second is in the end of Eridanus. The third is in the right foote of the Centaure."〔Knobel, p. 416.〕 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「Canopus」の詳細全文を読む スポンサード リンク
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