Canis Major
What is Canis Major?
Constellations· Winter evenings (N) · southeast of Orion's belt, the brightest star. Orion's great hunting dog, with Sirius, the brightest star in the night sky, on its collar and Adhara and Wezen below forming the body. Ancient Egypt timed the Nile flood and the new year by Sirius's first dawn rising.
📍 Visible from where you are right now — computed in your browser
bearing · altitude · rise time · best time tonight
Where Canis Major is in your sky right now: https://nowsky.org/solar/sky?sel=con:Canis Major — location and time set automatically, no login.
Stars of the figure
| Star | Magnitude |
|---|---|
| Sirius | -1.5 |
| Adhara | 1.5 |
| Wezen | 1.8 |
| Mirzam | 2.0 |
| Furud | 3.0 |
| Omicron2 Canis Majoris | 3.0 |
The 6 brightest of the 9 stars used in the figure (8 lines). Lower magnitude means brighter.
Deep-sky objects near this constellation
Constellation basics
| Season | winter evenings, January–March |
|---|---|
| Brightest star | Sirius (−1.5, brightest star in the sky) |
| How to find | extend Orion's belt southeast |
| Area rank | 43rd of 88 |
Figures are representative approximations. Source: compiled from NASA and IAU public data.
Frequently asked
- When can I see Canis Major?
- winter evenings, January–March.
- How do I find Canis Major?
- extend Orion's belt southeast.
- What is the brightest star in Canis Major?
- Sirius, magnitude -1.5.
- Where is Canis Major in the sky right now?
- Open the sky view for your location and time and it shows the position in the sky right now.
Was Sirius red? — the puzzle of the ancient records
Ptolemy's Almagest classed Sirius as a red star. Seneca and Horace also spoke of its red light, and Chinese records mix white and red. Sirius today is blue-white to everyone, so whether the star changed colour in two thousand years was a long-running debate, and a hypothesis was even proposed that the white dwarf Sirius B was then a red giant.
Astrophysics does not accept it: the passage of Sirius B from red giant to white dwarf takes hundreds of thousands of years, not thousands, and would have left traces. The prevailing reading now is that the writers described Sirius flickering red near the horizon through atmospheric scattering, or that "red" was an idiom for fierce brightness. Even the recorded colour of the brightest star in the night sky becomes a question of philology.
The constellation in depth
Canis Major is the dog that follows the hunter Orion, sometimes identified with Laelaps, the hound that never failed to catch its prey. Sirius means "scorching" in Greek; because it rose with the Sun at midsummer dawn, the hottest weeks of the year became the "dog days". Greek writers also called Sirius the Dog Star, and its heliacal rising marked the flooding of the Nile for the Egyptians every summer.
Sirius appears so bright because it is close, 8.6 light-years away, and it is orbited every 50 years by Sirius B, a white dwarf the size of Earth with the mass of the Sun. Adhara to the south is the brightest star in the sky in ultraviolet light. The constellation also holds VY Canis Majoris, one of the largest stars known, and the bright open cluster M41.
On winter evenings extend the line of Orion's belt down to the southeast and you reach Sirius, unmistakably bright and twinkling in colours because it sits low in turbulent air. Below it, Adhara and Wezen form the dog's body and legs. Set the Sky view to a February evening to see the whole figure in the south. Low in the south, the dog is easily washed out by haze, so pick a clear, crisp night for the best view.
Related
Figures are representative approximations. Simulated positions use J2000 mean elements.