Ursa Major
UMa · genitive Ursae Majoris · northern sky
At a glance
- Catalogued stars
- 214
- Visible to the eye
- 214 stars
- Brightest star
- Alioth (1.76)
- Best seen
- March
- Declination span
- +31.5° to +63.1°
- Nearest star
- Groombridge 1830 · 29.7 ly
Visible from everywhere north of about 27°S.
When and where to look for Ursa Major
Ursa Major crosses the meridian — its highest point in the sky — at local midnight around March, which makes the months from February to April the easiest time to find it in the evening. It spans declinations +31.5° to +63.1°, so visible from everywhere north of about 27°S.
The quickest way to find it is to open the live AR sky map and point your phone at the sky — if Ursa Major is above your horizon right now, its figure is drawn in the position it genuinely occupies above you.
Brightest stars in Ursa Major
| Star | Mag | Type | Distance |
|---|---|---|---|
| Alioth77Eps UMa | 1.76 | A0p | 82.6 ly |
| Dubhe50Alp UMa | 1.81 | F7V comp | 122.9 ly |
| Alkaid85Eta UMa | 1.85 | B3V SB | 103.9 ly |
| Mizar79Zet UMa | 2.23 | A2V | 85.8 ly |
| Merak48Bet UMa | 2.34 | A1V | 79.7 ly |
| Phecda64Gam UMa | 2.41 | A0V SB | 83.2 ly |
Magnitude runs backwards: lower numbers are brighter, and anything below about 6.5 is beyond the naked eye under a dark sky.
What Ursa Major is made of
The catalogue lists 214 stars within Ursa Major, of which 214 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 Groombridge 1830 at 29.7 light years. The most distant is HD 88651 at roughly 2,132 light years — stars that appear side by side here are nothing of the sort.