Canis Major Constellation
Canis Major is the ‘Big Dog’ constellation and has both mythological references and great significance as it includes the brightest star in the sky known as the dog star. As a constellation that is both easy to locate and trace, it is popular for amateur stargazers. The constellation forms part of both the winter hexagon and winter triangle. It shares folklore stories with a several nearby significant constellations including Canis Minor and Orion.
The Canis Major constellation is one of the original 48 constellations listed by the Egyptian mathematician Ptolemy, who lived under Roman rule in Alexandria in the 2nd century. These constellations formed the basis for the modern list agreed by the IAU. Constellations from the southern hemisphere, unable to be seen from the Mediterranean, represent the majority of the more recent additions to the list.
As the earth moves in its orbit around the sun, each night you are looking at a different portion of the sky. When looking at stars it is important to be aware of what is within your view. Northern hemisphere stargazers can group constellations into 3 groups; circumpolar, summer and winter constellations. The circumpolar constellations are in the north sky, appear to move around the north star and are visible throughout the year. The constellations in the south sky are only visible for part of the year and are grouped as either summer or winter constellations. Each is visible from between 4 to 10 months.
It is important to be aware of the specific time of year and hour of the night when deciding what to look for. These pages below show the constellations in each group so you can find the constellations that interest you.
CIRCUMPOLAR (year around) – Ursa Major – Cassiopeia – Ursa Minor – Draco – Cepheus
WINTER – Pegasus – Pisces – Aries – Auriga – Taurus – Orion – Canis Major – Canis Minor – Gemini – Lynx – Cancer – Leo – Winter Hexagon
SUMMER – Virgo – Libra – Scorpius -Bootes – Hercules – Lyra – Ophiuchus – Sagittarius – Aquila – Cygnus – Capricornus – Aquarius
Or use this guide to easily see which constellations are easiest to find right now:
Canis Major Quick Facts:
Symbolism: Big Dog
Brightest star: Sirius, -1.44 magnitude (brightest star in the night sky)
Stars brighter than 3 magnitude: 5
Primary stars: 10 (Tail, Hips, Back Leg, Chest, Front Leg, Front Lower Body, Back Lower Body, Neck, Ear, Nose)
Latitude: 11.03 – 32.25 degrees south
Northern Hemisphere Season: Winter (January – March)
Which months can you see Canis Major constellation?
Canis Major is visible in the night sky from August to May. Canis Major lies between 10 degrees south and 20 degrees north latitude. Therefore the higher your latitude the shorter your opportunity to see Canis Major and the lower it will pass in the sky.
- Early evening viewers (pre 21:00) can find the constellation from January in the north east sky until May in the north west sky. Canis Major will be visible overhead from February to April.
- Mid evening viewers (21:00-23:30) can find the constellation from November in the north east sky until March in the northwest sky. Canis Major will be visible overhead in from January to February.
- Late evening viewers (after 23:30) can find the constellation from October in the north east sky until January in the north west sky. Canis Major will be visible overhead from November to January.
- Early morning viewers can find the constellation from August in the north east sky to December in the north west sky. Canis Major will be visible overhead from from October to November.
Canis Major is not possible to see throughout summer, as it passes in the daytime sky. As the constellation declination is at southern latitudes, it remains below the equator for most northern hemisphere latitudes at the beginning of winter. However, it becomes most visible in the southern sky during winter from January to March. At its maximum range it is possible to see at latitudes between +60 and -90. The lower latitudes will have visibility for longer periods of the year.
Best time to see Canis Major:
Best visible at 21:00 in February
August: only visible briefly before sunrise. Rising in south east sky at 04:30 and reaches a point 15 degrees above the horizon by sunrise.
September: rises in south east sky at 02:30 and reaches a point 35 degrees above the horizon by sunrise.
October: rises in south east sky at 01:00 and reaches its peak 40 degrees above the southern horizon at 06:00 shortly before sunrise.
November: rises in south east sky at 22:00 and reaches its peak 40 degrees above the southern horizon at 03:00. It will then lower in the south west sky until sunrise when it will be 25 degrees above the southwest horizon.
December: rises in south east sky at 20:00 and reaches its peak 40 degrees above the southern horizon at 01:00. It will then lower in the south west sky until it begins to be only partially visible from 05:30.
January: rises in south east sky at 18:30 and reaches its peak 40 degrees above the southern horizon at 23:00. It will then lower in the south west sky until it begins to be only partially visible from 03:30.
February: visible 25 degrees above the south east horizon at sunset and reaches its peak 40 degrees above the southern horizon at 21:00. It will then lower in the south west sky until it begins to be only partially visible from 01:00.
March: visible 40 degrees above the south horizon at sunset and reaches its peak in the southern sky at 19:00. It will then lower in the south west sky until it begins to be only partially visible from 23:30.
April: visible 35 degrees above the south west horizon at sunset. It will then lower towards the horizon until it begins to be only partially visible from 22:00.
May: only visible briefly after sunset. Appears at 15 degrees above the south west horizon until it begins to be only partially visible from 21:00.
Trajectory: The constellation is between 30-10 degrees south which means it is in the southern sky for all northern hemisphere viewers. The constellation will rise in the south east and set in the south of west passing low in the southern sky.
Not the right time for Canis Major? Have a look what constellations you can see tonight.
How to find Canis Major constellation?
Canis Major constellation is visible in the southern sky during winter months for observers in the northern hemisphere. To find Canis Major without any reference points is possible as ‘Sirius’ – the brightest star in the sky – is part of this constellation. Sirius marks the chest of the dog and regardless how you locate the constellations you will use this star that is significantly brighter than any others to identify the remainder of the constellation.
Canis Major is best located using either the small and easily identified asterism of Orion‘s belt, or the large asterism of the winter hexagon. To identify Sirius using Orion’s belt, move westward approximately 7 times the length of the belt west following an imaginary continuation of the belt. If you have identified the winter hexagon or winter triangle then Sirius forms a corner in each asterism.
Learn how to form the shape of Canis Major constellation
The body of the dog is the easiest to identify, with the 5 brightest stars in the constellation marking the extremities.
- Sirius is by far the brightest star in this area of the sky, and represents the chest of the dog.
- East of Sirius around the length of Orion’s belt is Mirzam marking the front feet
- South-west of Sirius – located around 3 times the length of the front leg, the star Wezen marks the hips at the backend of the dog.
- The tail continues in the same direction and is a similar length as the front leg marked by Aludra.
- From Wezen the back leg is slightly shorter than the front leg. Adhara is the second brightest star in the constellation marking the back foot.
The head of the dog is less apparent than the body. There are 3 stars forming a triangle to the west of Sirius. They are far dimmer but with a clear visual idea of the body it becomes easier to identify the head.
Canis Major in the Ancient World
Greek mythology of Laelaps
The Canis Major constellation relates to the Greek mythology story of Laelaps and the Teumessian fox. Laelaps was the hunting dog who would always catch its prey. Zeus gave Laelaps as a gift to Europa of Crete and in time came under ownership of Procris. Procris entrusted it to her husband Cephalus along with a spear that never missed. However, motivated by jealousy she hid in the forest to monitor him during a hunt and he accidentally killed her with the spear.
Cephalus was banished for the murder and during his exile was commissioned to hunt the Teumessian fox. The Teumessian fox was a gigantic fox that the gods had created as a punishment against the Thebes and was destined never to be caught. The god given destiny of each created a paradox and Zeus turned them both to stone.
Sirius was an important star in ancient Egypt where it signalled the seasonal floods. The calendar of the Pharaohs began on the first day Sirius appeared on the horizon.
Canis Majoris was recognised in the tales of the constellations as the hunting dog of Orion. The dog forms part of a wider story of the relationship between the constellations as part of Orions battle with Taurus the bull. The dog trails Orion but also pursues the hare, represented by the constellation Lepus.
Main stars of Canis Major
Sirius (-1.46m, 8.6ly, 20 suns, #1)
Sirius, from the Greek word ‘scorching’, is the brightest star visible from earth with apparent magnitude of -1.46. Sirius is a dual star at a distance of 8.6 light years. The white dwarf star is 20 times the size of the sun. It is the 5th closest star to earth (discluding the sun), but only Alpha Centaurus ahead of it is prominent. Because of its prominence the star has over 50 names across different ancient cultures, particularly in reference to dogs and its identity as the dog star. Sirius forms part of both the Winter Hexagon and Winter Triangle.
In ancient times Sirius would appear in mid to low latitudes in the northern hemisphere in mid July. Its appearance marked the beginning of the Egyptian year and was the indicator of seasonal floods. In many Mediterranean cultures the appearance of Sirius marked the ‘dog days’ where intense heatwaves would impact people and their animals and crops. Sirius has a latitude of 17 degrees south and became important for Polynesian sailors as an indicator of the path of true east-west. The star marks the chest of the dog in Canis Major.
Adhara (+1.5m, 430ly, 11k suns, #22)
Adhara, from the Arabic word for ‘virgins’, is the 22nd brightest star with an apparent magnitude of +1.5. 4.7 million years ago it was the brightest star in the night sky with an apparent magnitude of -3.99. Adhara is 430 light years from earth. It is 11,00 times the size of the sun. The Arabic name Adhara originates from its inclusion in a navigation asterism of the virgins. The star marks the back feet of the dog in Canis Major.
Wezen (+1.83, 1,792ly, 41m suns, #36)
Wezen, from the Arabic word for ‘weight’, is the 36th brightest star with an apparent magnitude of +1.83. Its distance is 1,792 light years from earth. It is a yellow supergiant over 40 million times bigger than the sun. The name weight is said to be in reference to the low trajectory of the star through the sky when viewed from the northern hemisphere. But the name is also accurate given the size, luminosity and burn rate of the star. It is the 3rd brightest star over 1,000 light years from earth. The star marks the hips of the dog in Canis Major.
Mirzam (+1.98m, 499ly, 3.8k suns, #46)
Mirzam, from the Arabic word for ‘heralding’, is the 46th brightest star with an apparent magnitude of +1.98. Its distance is 499 light years from earth. It is a blue-white giant over 3800 times the size of the sun. The name references it rising above the horizon prior to Sirius. The star marks the front feet of the dog in Canis Major.
Aludra (+2.45m, 3,198ly, 750k suns, #87)
Aludra, which is an Arabic female name, is the 87th brightest star with an apparent magnitude of +2.45. Its distance is 3,198 light years from earth. It is a blue-white supergiant 750,000 times the size of the sun. The name Aludra is in reference to the star as one of the stars in the asterism ‘the virgins’. The star marks the tail of the dog in Canis Major.
Deep sky objects
Messier 41 – A cluster of 100 stars around 2,300 light years away with an apparent magnitude of 4.5.
Canis Major Dwarf Galaxy – The nearest galaxy located 25,000 light years away. The galaxy has over a billion stars but is difficult to observe as it is obscured by the milky way.
NGC2207 & IC2163 – only possible to see with a telescope, with apparent magnitudes of 12.2 & 11.6 respectively. These two colliding galaxies are in the process of merging.
Wadi Rum is one of the best locations in the world to see the full beauty of the stars. Combining high altitudes, clear skies and no light pollution. You may be surprised how many stars are visible to the naked eye. Come with us and spend a night under the stars.