Canis Major the Greater Dog
Canis Major, the big Dog of the skies, passes directly overhead in southern Australia.  He is depicted looking towards his master, the giant Orion, and the fleeing shape of Lepus the Hare, underneath Orion's feet.    As he rises in the east with Orion he seems to be lying on his back in the Milky Way, with several bright stars marking his spine and legs. 

Image ©
This old chart shows the placement of Canis Major 
in the sky near Orion and Lepus.

On his shoulder shines Sirius, the brightest star in the sky.  Most of the mythology of Canis Major is connected to Sirius as the constellation itself did not take on it current form until Roman times.  Sirius is not the closest star though it is still close to us, lying at 8.7 light years away.  It is a hot  white star that will shine brightly for a long time to come.  It is also a known binary system, with a tiny white dwarf star, coloquially known as 'the Pup', circling the brighter primary every 50 years.  Most of the time it is lost in the glare of the primary but it can swing out far enough to be seen in amateur telescopes.  This will next be possible in the years 2020 to 2025.

Sirius means "Scorching", named so by the ancient Greeks as it rose and set with the Sun during the northern hemisphere Summer 3000 years ago.  It was thought that the combined heat of the two stars caused the hot weather of late Summer.  It was also commonly known as the Dog star, a tradition that reaches far back before Babylonian times.  This is also where the expression "the dog days of Summer" comes from. 

Sirius was important to the ancient Egyptians.  They watched for the heliacal rising of Sirius to indicate the start of the annual flooding of the Nile River  (a heliacal rising is when a star is first seen in the eastern sky before dawn after it has "passed behind" the Sun).  Some references connect Sirius with the god Osiris, as the name is similar in sound.  Others connect Sirius with Anubis the Jackal-headed god.  It is interesting to note that the Chinese connected Sirius with a canine figure as well, but the Australian Aborigines saw it as an eagle.

As another point of interest, even though Sirius passes overhead in southern Australia it is visible at some point every night of the year!  During late June and early July it is possible to see Sirius setting in the west just after sunset and then see it rise in the east just before sunrise the next day.  This makes it the brightest non-circumpolar star that you can see rise and set in one night.

Mirzam the Announcer (beta (b) Canis majoris) marks the front paw of the Dog.  It was so called as it heralded the imminent rising of Sirius.

Wezen the Weight (delta (d) Canis majoris)  marks the base of the tail.  It was called this as apparently from the northern hemisphere it seems reluctant to rise above the horizon.  This would be an optical illusion as a result of the star's far southerly declination.  Here in southern Australia it rises at the same time as Sirius.

This article is ©2000 Stargazers Astronomy Shop

Return to Star Lore Index