Canis Major is a southern celestial hemisphere constellation. It was one of Ptolemy's 48 constellations in the second century, and it is now one of the 88 modern constellations. Its name means "larger dog" in contrast to Canis Minor, which means "lesser dog" in Latin; both figures are usually seen in the sky following the constellation of Orion the hunter. The Milky Way travels through Canis Major, and it contains multiple open clusters, the most famous of which is M41.
Sirius, the brightest star in the night sky and the "dog star," is found in Canis Major. Because of its close closeness to the Solar System, it is extremely bright. The constellation's other bright stars, on the other hand, are stars with a far distance and a high luminosity. Epsilon Canis Majoris (Adhara) is the constellation's second-brightest star and the brightest source of extreme ultraviolet radiation in the night sky, with a magnitude of 1.5. The yellow-white supergiant Delta (Wezen) is next in brightness at 1.8, followed by 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) at 3.0. The red hypergiant VY Canis Majoris is one of the largest known stars, whereas the neutron star RX Canis Minoris is one of the smallest. |
Mythology
Western astronomy Sirius was considered as an arrow shooting towards Orion in ancient Mesopotamia, while the southern stars of Canis Major and a section of Puppis were viewed as a bow, designated BAN in the Three Stars Each tablets dating to circa 1100 BC. The arrow, Sirius, was also linked with the warrior Ninurta, and the bow with Ishtar, daughter of Enlil, in the later Babylonian astronomy and astrological compendium MUL.APIN. (Rogers 1998) Ninurta was linked to the later deity Marduk, who was worshipped as the primary deity in Babylon and was supposed to have slain the ocean goddess Tiamat with a giant bow. (Wagman 2003) The Ancient Greeks replaced the picture of a bow and arrow with one of the dogs. (Rogers 1998) Canis Major was the dog Laelaps, a gift from Zeus to Europa; or the hound of Procris, Diana's nymph; or the one given by Aurora to Cephalus, which was so famous for its speed that Zeus hoisted it to the sky. (Allen 1963) It was also thought to represent one of Orion's hunting dogs (Ridpath & Tirion 2001), following Lepus the Hare or assisting Orion in the struggle against Taurus the Bull, and Aratos, Homer, and Hesiod all refer to it in this fashion. The ancient Greeks only mention one dog, but Canis Minor appears as Orion's second dog by the time of the Romans. Canis Sequens and Canis Alter are two more names for this species. The name Canis Syrius was used in the Alfonsine tables of 1521. (Allen 1963) Canis Major is also known as Custos Europae, the dog that guarded Europa but failed to prevent her abduction by Jupiter in the form of a bull, and Janitor Lethaeus, "the watchdog" in Roman mythology. (Allen 1963) The constellation was renamed al-Kalb al-Akbar, "the Greater Dog," in mediaeval Arab astrology, and was written as Alcheleb Alachbar by 17th-century writer Edmund Chilmead. Orion is known as Kalb al-Jabbr, "the Dog of the Giant," according to Islamic scholar Ab Rayn al-Brn. (Allen 1963) Shepherds in Tunisia's Merazig watch for six constellations that signal the end of the dry, hot season. Merzem, one of them, is the herald of two weeks of hot weather and includes the stars of Canis Major and Canis Minor. (Oxby 1999) |
Non-western astronomy
The present constellation of Canis Major is found in the Vermilion Bird (南方朱雀; Nán Fāng Zhū Què) in Chinese astrology, where the stars were divided into various asterisms. The Military Market (軍市; Jūnshì) was a ring of stars that included Nu3, Beta, Xi1 and Xi2, as well as certain Lepus stars. (Schlegel 1967). The Military Market was centred on the Wild Cockerel (野雞; Yějī), though it is unclear which stars depicted what. They could have been the stars Omicron and Pi Canis Majoris, according to Schlegel (Schlegel 1967), while Beta or Nu2 have also been suggested. Sirius was Tiānláng (天狼), the Celestial Wolf, which symbolised invasion and plunder. The asterism Húshǐ (弧矢), the celestial Bow and Arrow, was found southeast of the Wolf and was thought to contain Delta, Epsilon, Eta, Kappa Canis Majoris and Delta Velorum. Alternatively, Omicron2 and Eta were shown as the arrow, which was aimed at Sirius (the Wolf), while the bow was made up of Kappa, Epsilon, Sigma, Delta, and 164 Canis Majoris, as well as Pi and Omicron Puppis. (Schlegel 1967) The figure of Canis Major was regarded as a separate entity by both the Mori and the Tuamotus peoples, though it was sometimes subsumed into other constellations. Te Huizinga-o-Rehua, also known as Te Putahi-nui-o-Rehua and Te Kahui-Takurua, was a Mori constellation that encompassed both Canis Minor and Canis Major, as well as other nearby stars. (Makemson 1941) Taumata-o-Rehua, also known as Pukawanui, the Mirror of Rehua, was formed in Canis Major from an unknown group of stars. (Makemson 1941) Sirius was given the names Rehua and Takarua, which corresponded to two of the constellation's names, while Rehua was also a name given to other stars in several Mori tribes and other Polynesian cosmologies. (Makemson 1941) "The abiding assemblage," as the Tuamotu people termed Canis Major Muihanga-hetika-o-Takurua. Wunbula (Bat) and his two wives Murrumbool (Mrs Brown Snake) and Moodtha (Mrs Black Snake) were three stars of Canis Major seen by the Tharumba people of the Shoalhaven River; wary of following their husband around, the women try to bury him as he is hunting a wombat down its hole. He spears them, and they become the constellation Munowra in the sky. (Ridley 1875) Sigma Canis Majoris was Unurgunite (which has now been the official name of this star) to the Boorong people of Victoria, and its flanking stars Delta and Epsilon were his two wives. (Hamacher 2010) The moon (Mityan, "native cat") attempted to seduce the second wife (Epsilon), but Unurgunite attacked him, and he has been wandering the skies ever since. Canis Major is a constellation in the Southern Hemisphere's summer (or northern hemisphere's winter) sky, bordered to the north by Monoceros, to the east and southeast by Puppis, to the southwest by Columba, and the west by Lepus. The International Astronomical Union established the three-letter abbreviation "CMa" for the constellation in 1922. (Russell 1925) The official constellation boundaries, as defined by Belgian astronomer Eugène Delporte in 1930, are defined by a quadrilateral; the right ascension coordinates of these borders are between 06h 12.5m and 07h 27.5m in the equatorial coordinate system, while the declination coordinates are between 11.03° and 33.25°. It ranks 43rd among the 88 currently recognised constellations, covering 380 square degrees or 0.921 percent of the sky. (Bagnall 2012) |
Deep sky objects
The Milky Way's band passes past Canis Major, with just patchy interstellar dust clouds obscuring it. Many stars can be seen in binoculars in the north-eastern corner of the constellation, as well as in a triangular area between Adhara, Wezen, and Aludra.
M41 – Open Cluster
NGC 2360 – Open Cluster
NGC 2362 – Open Cluster
NGC 2354 – Open Cluster
NGC 2359 – Emission Nebula (Thor’s helmet)
NGC 2298 – Globular Cluster
NGC 2207 and IC 2163 – Colliding Galaxies
The Milky Way's band passes past Canis Major, with just patchy interstellar dust clouds obscuring it. Many stars can be seen in binoculars in the north-eastern corner of the constellation, as well as in a triangular area between Adhara, Wezen, and Aludra.
M41 – Open Cluster
NGC 2360 – Open Cluster
NGC 2362 – Open Cluster
NGC 2354 – Open Cluster
NGC 2359 – Emission Nebula (Thor’s helmet)
NGC 2298 – Globular Cluster
NGC 2207 and IC 2163 – Colliding Galaxies
Main stars – 8
Bayer stars – 32
Stars with planets – 7
Stars brighter than magnitude 3.0 – 5
Stars within 32ly – 1
Bordering
constellations
Bayer stars – 32
Stars with planets – 7
Stars brighter than magnitude 3.0 – 5
Stars within 32ly – 1
Bordering
constellations
- Monoceros
- Lepus
- Columba
- Puppis