Constellation Canis Major

Constellations > Big Dog

Big Dog is a constellation located in the southern sky, and the name “Canis Major” is translated from Latin as “Big Dog”.

In mythology, it was a dog accompanying the hunter Orion. Often depicted in the process of hunting a hare (constellation Hare). The smaller dog is the constellation Canis Minor. Both were listed in the second century by Ptolemy.

Sirius is the brightest star in the constellation Canis Major and the brightest in the sky. Also, several notable objects live in the constellation: the Canis Major Dwarf Galaxy, the open cluster Messier 41, the emission nebula NGC 2359 (Thor’s Helmet) and the merging spiral galaxies NGC 2207 and IC 2163.

Constellation Canis Major

An object Designation Meaning of the name Object type Magnitude
one M41 No Open cluster 4.60
2 Sirius “Brilliant” Binary star system -1.46
3 Adara “Virgin” Binary star system 1.50
4 Vesen “Severity” Yellow-white supergiant 1.83
five Mirtsam “Herald” Beta Cepheid class variable 1.98
6 Aludra “Virginity” Blue supergiant 2.45
7 Zeta Big Dog (Furud) “Solitary” Binary star system 3.02
eight Big Dog Kappa No Blue subgiant 3.50
nine Theta Big Dog No Orange giant 4.08
10 Gamma Big Dog (Mulifen) “The Sworn Star” Blue-white giant 4.10
eleven Iota Big Dog No Blue supergiant 4.40

Facts, position and map

The largest constellation Canis Major is in 43rd place with an area of ​​380 square degrees. Occupies the second quadrant of the southern hemisphere (SQ1). It can be found at latitudes between + 60 ° and -90 °. Adjacent to the Unicorn, Hare, Dove and Poop.

Big Dog
Lat. title Canis major
Reduction CMa
Symbol Big Dog
Right ascension from 6h 07m up to 7h 22m
Declination from -33 ° to -11 °
Square 380 sq. degrees
(43rd place)
The brightest stars
(value <3m)
  • Sirius (α CMa) -1.46m
  • Adar (ε CMa) 1.5m
  • Vesen (δ CMa) 1.84m
  • Aludra (η CMa) 2.45m
Meteor showers No
Nearby constellations
  • Unicorn
  • Hare
  • Pigeon
  • Stern
The constellation is visible in latitudes from + 57 ° to -90 °.
The best time for observation on the territory of Ukraine is December, January.

It contains one Messier object – the Messier 41 star cluster (NGC 2287), as well as 4 stars with planets. The brightest is Sirius (not only in the constellation, but throughout the sky). There are no meteor showers. It is part of the Orion family, where Orion, the Unicorn, the Hare and the Little Dog are also present. Consider the view of the constellation Canis Major in the photo.

Constellation Canis Major


Most often, a dog was seen in the role of Big Dog, which accompanied Orion on a hunt. It is depicted standing on its hind legs, chasing a hare (constellation Hare). Manilius described the Dog as “a dog with a flaming face” because it holds the brightest star Sirius in its jaw.

The myths also have a story about the fastest dog in the world – Lelap. She could catch whatever she was chasing. Zeus gave it to Europe, as well as a spear with which you can’t miss. But the gift turned out to be fatal, since her husband Cephalus accidentally killed his wife while hunting.

Cephalus took the dog to Thebes to catch a fox, which brings many troubles for the locals. Like Lelap, she was incredibly fast. They would run indefinitely if Zeus had not turned them into stones. He put the dog in heaven.

Main stars

Sirius (Alpha Canis Major) is a binary star with an apparent visual magnitude of -1.42. It is 8.6 light years distant. Also known as the Star of the Dog, it is the brightest star in the sky and the 5th closest to the solar system.

Sirius A is a white main sequence star, and Sirius B is a white dwarf orbiting the main sequence every 50 years. The distance between them can be from 8.1 to 31.5 AU. The satellite cannot be seen without professional equipment.

Sirius A and Sirius B

Sirius A and Sirius B

Sirius A belongs to spectral class A1V and is 2 times the solar mass, and the dwarf is DA2 with 0.98 solar mass (one of the most massive white dwarfs). The magnitude of Sirius A is 1.42 and Sirius B is 11.18. The age of the stellar system is 200-300 million years.

The name “Sirius” has Greek roots “Σείριος” – “scorching”, “flaming” or “burning”. In ancient times, it appeared before sunrise in the hottest summer period – the Days of Dogs. The Greeks and Romans thought the star was to blame for the summer heat.

Double star Sirius through the eyes of an artist

Double star Sirius through the eyes of an artist

In Egypt, Sirius fell on the flood of the Nile. The stellar heliacal growth before the annual flood and the summer solstice played a decisive role in the compilation of the Egyptian calendar in the era of the Celestial Empire.

Together with the stars Rigel (Orion), Aldebaran (Taurus), Capella (Charioteer), Castor (Gemini) and Procyon (Lesser Dog) forms the Winter Hexagon (Winter Circle) asterism, which appears in the northern sky between December and March.

Sirius is also part of the Winter Triangle (Great Southern Triangle), along with Procyon and Betelgeuse (Orion).

Adara (Epsilon Canis Major) is a binary star, 430 light years distant. The main component belongs to spectral type B2 with a magnitude of 1.5. It is one of the brightest UV sources known. The satellite is 7.5 in magnitude, and it is at a distance of 7.5 ” from the main one.

Ranked second in brightness in the constellation and 24th overall. The name comes from the Arabic aðāra – “virgin”. About 4.7 million years ago, Adhara was the brightest star in the sky, located 34 light years away and with a magnitude of -3.99. No other star has ever been this bright and will not be in the next 5 million years.

Vesen (Canis Major Delta) is a yellow-white F-type supergiant about 1800 light years and a magnitude of 1.83. It takes the third position in terms of brightness. Vesen can be found about 10 degrees southeast of Sirius. The name was derived from the Arabic “al-wazn” – “heaviness”. Reached the age of 10 million years, so within 100,000 it transforms into a red supergiant, and then explodes into a supernova.

Mirtsam (Beta Canis Major) is a blue-white giant with a brightness of 1.95-2.00 and a distance of 500 light years. This is the Beta Cephei variable (brightness changes due to ripples on the surface). The star rises before Sirius.

Aludra (This Big Dog) is a variable star of the Deneb type, with a magnitude of 2.38-2.48. It is a blue supergiant 3,000 light years distant. Approaching the last stages of its existence. It is expected to go supernova within the next few million years. From Arabic al-‘aðrā means “virgin”.

Tau Canis Majoris is an eclipsing spectroscopic binary about 3,200 light years distant. It is the brightest star in the open cluster NGC 2362 (Caldwell 64).

Tau Big Dog

Tau Big Dog

It is an O-type blue supergiant classified as a Beta Lyrae type variable. Visibility: 4.32-4.37 with a period of 1.28 days.

Furud (Zeta Canis Major) is a spectroscopic binary star 336 light years distant and has an apparent magnitude of 3.02. The brighter one is a blue-white B-type main sequence dwarf. The satellite is an invisible star. They revolve around a common center every 675 days. From Arabic “al-furud” means “single”.

Mulifen (Gamma Canis Major) is a blue-white B-type giant, 402 light years distant. Visible visual value – 4.11.

Celestial objects

Messier 41 (M41, NGC 2287) is an open cluster 4 degrees south of Sirius. It is 25-26 light years in diameter and 190-240 million years old. Contains approximately 100 stars. The brightest is a K3-type giant located near the center. Several red giants have also been spotted.

Messier 41

Messier 41

It is 2,300 light years distant with an apparent magnitude of 4.5. Found in the 17th century by the Italian astronomer Giovanni Batista Hodiern.

The Canis Major dwarf galaxy is an irregular galaxy (elliptical). It is separated by 25,000 light years, so it is considered one of the closest. The distance from the Galactic center is 42 thousand light years.

Dwarf galaxy in Canis Major

Dwarf galaxy in Canis Major

It contains a billion stars, among which there are many red giants. It was found only in 2003 by an international group of astronomers. It is difficult to observe because it lies behind the plane of the Milky Way, obscured by stars, dust and gas.

Since the main body is highly degraded, it can be influenced by the gravitational field of the Milky Way. It is associated with such clusters as NGC 1851, NGC 1904, and NGC 2808.

NGC 2359 (Thor’s Helmet) is an emission nebula.

NGC 2359

NGC 2359

It is 30 light-years in size and 15,000 light-years distant from us. It forms around the central star Wolf-Rayet, an extremely hot giant that will soon explode in a supernova.

NGC 2207 and IC 2163 are merging spiral galaxies 80 million light years apart. They were found by the astronomer from England John Herschel in 1835.

The visible values ​​are 12.2 and 11.6. In recent decades, three supernovae have been observed in NGC 2207: SN 1975A (1975), SN 1999ec (1999), and SN 2003H (2003).

The galaxies are in the process of tidal merging. The larger one draws stars and other materials from the smaller one.

You can study the constellation Canis Major (its stars and objects) more closely if you use our online 3D models and telescope. For an independent search, a static or moving map of the starry sky is suitable.

Constellations of the winter sky

December Aries Whale Eridanus Oven Clock Southern Hydra Perseus Triangle
January Chisel Dora Fish Table Mountain Orion Mesh Taurus
February Charioteer Giraffe Big Dog Dove Gemini Hare Unicorn Painter


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