Canis Major
Canis Major, holding Sirius, the brightest star in the night sky. It is the faithful hunting dog that follows Orion.
Science
The scienceThe chief star Sirius is the brightest star in the night sky, the most dazzling of all stars visible from Earth apart from the Sun. This is partly because the star itself is unusually bright, but mostly because it lies a mere 8.6 light-years away, very close by. Sirius is in fact a binary of two stars; orbiting it is a white dwarf known as "Sirius B," a star with the mass of the Sun compressed into a body the size of Earth, one of the first white dwarfs ever discovered. In ancient Egypt, the dawn rising of Sirius was taken as the signal of the Nile's flood and used as the basis of the calendar.
Mythology
How it became a constellationCanis Major is drawn as the faithful hunting dog that follows the giant hunter Orion. It trails at Orion's feet across the winter sky, chasing the hare Lepus. Another legend calls it Laelaps, a magical hound that never let its quarry escape; set to chase a fox fated never to be caught, it fell into the paradox of "the dog that always catches and the fox that is never caught," whereupon Zeus turned both to stone and set them in the sky. The name of its chief star, Sirius, means "the scorching one," "the dazzling one" in Greek.
Observing Guide
how to observe🔭 How to find it
On a winter evening, extend Orion's Belt straight down to the left (southeast) to reach Sirius, the brightest star in the night sky; this dazzling star of magnitude -1.5 marks the nose of the great dog. Sirius is so bright and sparkles so white that it simply cannot be missed in the winter southern sky. Below Sirius, more stars form the dog's body and hind legs.
✨ What to look for
A little south of Sirius lies the bright open cluster M41, a hazy patch even to the naked eye and a lovely scatter of stars through binoculars. It is a venerable object, said to have been recorded by Aristotle in the 4th century BC as a "hazy spot." Straddling the edge of the Milky Way, it is surrounded by smaller clusters scattered nearby.
📍 Where to see it (US · Canada · UK · Australia)
From the US, Canis Major sits low in the southern sky on winter evenings (January–March), brilliant Sirius culminating only around 30–35° and often flashing in colours as it twinkles low down; from the UK and Canada it hugs the horizon and its southern stars (near −30°) barely rise. From Australia the great dog stands high overhead during the southern summer, Sirius blazing near the zenith.