Star Stars · In Canis Major
Mirzam
Mirzam, β Canis Majoris, is a blue-white bright giant in Canis Major: the 49th brightest star in the night sky.
Save the chart (SVG) Tactile chart (A4 SVG)
- Constellation
- Canis Major
- Designation
- β Canis Majoris
- Apparent magnitude
- 1.98 · 49th brightest star in the night sky
- Spectral class
- B1II/III
- Distance
- 493 light-years
- Highest at midnight
- late December
- Position (J2000)
- RA 06h 23m · Dec −17° 57′
A blue-white bright giant, around 28,000 K, like Rigel and Spica. About 64× brighter than the faintest star the eye can see. Gives off about 3,100 times the Sun's visible light. The light you are seeing left around 1533.
When to see it
On the night of Thu 24 Dec 2026, when it is highest around midnight, on each city’s own clock:
| From | Rises | Highest | Sets |
|---|---|---|---|
| London GMT | 19:47 | 00:10 · 21° | 04:33 |
| New York EST | 19:10 | 00:05 · 31° | 04:59 |
| Singapore GMT+8 | 19:18 | 01:15 · 71° | 07:12 |
| Sydney GMT+11 | 18:17 | 01:06 · 74° | 07:55 |
Common questions
- Can I see it from 50° north?
- Yes. It rises and sets, and at its highest it stands 22° up in the south.
- Can I see it from 35° south?
- Yes. It rises and sets, and at its highest it stands 73° up in the north.
- When is the best time of year to see it?
- Around late December, when it stands opposite the Sun and is highest at midnight. It comes round about two hours earlier each month, so by late March it is highest in the early evening, and in late September not until the hours before dawn.
- How far away is it, and how bright?
- It is 493 light-years away, and shines at magnitude 1.98 in our sky. From that far, the Sun would be a star of magnitude 10.7: too faint for the eye, a target for binoculars.
- Naked eye, binoculars or telescope?
- The naked eye, even from a city: at magnitude 1.98 it is brighter than the faintest stars a city sky still shows, about magnitude 4.5.
Look for
Start from Sirius: Mirzam is 5.5° west of it, three fingers at arm’s length.
Look for
From 50° north it climbs to 22°; from 35° north it climbs to 37°; from the equator it climbs to 72°; from 35° south it climbs to 73°.
Science
Mirzam’s surface is about 28,000 K, some 22,200 K hotter than the Sun’s 5,772 K, so its light is strongest at about 100 nm, in the ultraviolet, past the violet end of what the eye can see, where the Sun’s is strongest at 500 nm. Moved to 33 light-years, the distance astronomers compare stars at, it would shine at magnitude −3.9, brighter than Sirius, the brightest star in our sky.
Did you know
Against Sirius, the brighter star the hop starts from: Sirius looks 23 times as bright as Mirzam in our sky, but Sirius is 9 light-years away and Mirzam 493 light-years, so side by side Mirzam would give off 140 times as much light as Sirius.
Science
Mirzam is the 126th nearest to us of the 156 stars on these pages with a measured distance. Its nearest neighbour among them in space is Adhara, about 140 light-years from it; on our sky the two are 14° apart.
Look for
The Sun passes 41° north of Mirzam around late June, when it is highest at noon, in daylight: the weeks either side are its worst time of year. From 50° north it is above the horizon for about 9 hours a day, from 35° north about 10 and from 35° south about 14. It is 14° from the plane of the Milky Way.