Canis Major

Canis Major
Canis Major
Abbreviation CMa
Genitive Canis Majoris
Pronunciation , genitive
Symbolism the greater dog
Right ascension 06h 12.5m to 07h 27.5m[1]
Declination −11.03° to −33.25°[1]
Family Orion
Quadrant SQ2
Area 380 sq. deg. (43rd)
Main stars 8
Stars with planets 7
Stars brighter than 3.00m 5
Stars within 10.00 pc (32.62 ly) 1
Brightest star Sirius (α CMa) (−1.46m)
Nearest star Sirius (α CMa)
(8.60 ly, 2.64 pc)
Messier objects 1
Meteor showers None
Visible at latitudes between +60° and −90°.
Best visible at 21:00 (9 p.m.) during the month of February.

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. The Milky Way passes through Canis Major and several open clusters lie within its borders.

Canis Major contains Sirius, the brightest star in the night sky, known as the 'dog star'. It is bright because of its proximity to our Solar System. 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 one of the brightest sources of 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 Omicron1 at 3.0, and white spectroscopic binary Zeta (Furud), also at 3.0. The red hypergiant VY Canis Majoris is one of the largest stars known, while the neutron star RX J0720.4-3125 has a radius of a mere 5 km.


  • History and mythology 1
    • In western astronomy 1.1
    • In non-western astronomy 1.2
  • Characteristics 2
  • Notable features 3
    • Stars 3.1
    • Deep-sky objects 3.2
  • Notes 4
    • Cited texts 4.1
  • External links 5

History and mythology

In western astronomy

In ancient Mesopotamia, Sirius, named KAK.SI.DI 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.[2] 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.[3] The Ancient Greeks replaced the bow and arrow depiction with that of a dog.[4]

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.[5] It was also considered to represent one of Orion's hunting dogs,[6] 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.[5] Canis Syrius was the name used in the 1521 Alfonsine Tables.[5]

The Roman myth refers to Canis Major as Custos Europae, the dog guarding Europa but failing to prevent her abdu