Corona Borealis
CrB · genitive Coronae Borealis · northern sky
At a glance
- Catalogued stars
- 37
- Visible to the eye
- 37 stars
- Brightest star
- Alphecca (2.22)
- Best seen
- May
- Declination span
- +26.1° to +31.4°
- Nearest star
- 15Rho CrB · 56.2 ly
Visible from everywhere north of about 59°S.
When and where to look for Corona Borealis
Corona Borealis crosses the meridian — its highest point in the sky — at local midnight around May, which makes the months from April to June the easiest time to find it in the evening. It spans declinations +26.1° to +31.4°, so visible from everywhere north of about 59°S.
The quickest way to find it is to open the live AR sky map and point your phone at the sky — if Corona Borealis is above your horizon right now, its figure is drawn in the position it genuinely occupies above you.
Brightest stars in Corona Borealis
| Star | Mag | Type | Distance |
|---|---|---|---|
| Alphecca5Alp CrB | 2.22 | A0V | 75 ly |
| Nusakan3Bet CrB | 3.66 | F0p | 111.8 ly |
| 8Gam CrB | 3.81 | A1Vs | 146.1 ly |
| 4The CrB | 4.14 | B6Vnn | 375.3 ly |
| 13Eps CrB | 4.14 | K3III | 221.4 ly |
| 10Del CrB | 4.59 | G5III-IV | 170 ly |
Magnitude runs backwards: lower numbers are brighter, and anything below about 6.5 is beyond the naked eye under a dark sky.
What Corona Borealis is made of
The catalogue lists 37 stars within Corona Borealis, of which 37 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 15Rho CrB at 56.2 light years. The most distant is HD 141456 at roughly 1,026 light years — stars that appear side by side here are nothing of the sort.