Canis Major
CMa · genitive Canis Majoris · southern sky
At a glance
- Catalogued stars
- 148
- Visible to the eye
- 148 stars
- Brightest star
- Sirius (-1.46)
- Best seen
- December
- Declination span
- -30.1° to -12.0°
- Nearest star
- Sirius · 8.6 ly
Visible from everywhere south of about 60°N.
When and where to look for Canis Major
Canis Major crosses the meridian — its highest point in the sky — at local midnight around December, which makes the months from November to January the easiest time to find it in the evening. It spans declinations -30.1° to -12.0°, so visible from everywhere south of about 60°N.
The quickest way to find it is to open the live AR sky map and point your phone at the sky — if Canis Major is above your horizon right now, its figure is drawn in the position it genuinely occupies above you.
Brightest stars in Canis Major
| Star | Mag | Type | Distance |
|---|---|---|---|
| SiriusAlpha Canis Majoris | -1.46 | A1V | 8.6 ly |
| Adhara21Eps CMa | 1.50 | B2II | 405.2 ly |
| Wezen25Del CMa | 1.83 | F8Ia | 1,606.7 ly |
| Mirzam2Bet CMa | 1.98 | B1II/III | 492.7 ly |
| Aludra31Eta CMa | 2.45 | B5Ia | 1,988.8 ly |
| Furud1Zet CMa | 3.02 | B2.5V | 362.4 ly |
Magnitude runs backwards: lower numbers are brighter, and anything below about 6.5 is beyond the naked eye under a dark sky.
What Canis Major is made of
The catalogue lists 148 stars within Canis Major, of which 148 are magnitude 6.5 or brighter — the limit of what an unaided eye picks up under a genuinely dark sky. The rest need binoculars or a telescope.
Spectral make-up
Spectral class is a temperature ordering, running from O at around 30,000 K down to M below 3,500 K. A constellation is a direction, not a group, so this is simply what happens to lie along that line of sight.
The closest catalogued star in this direction is Sirius at 8.6 light years. The most distant is HD 53974 at roughly 3,048 light years — stars that appear side by side here are nothing of the sort.