Circinus
Cir · genitive Circini · southern sky
At a glance
- Catalogued stars
- 40
- Visible to the eye
- 40 stars
- Brightest star
- Alp Cir (3.18)
- Best seen
- April
- Declination span
- -65.0° to -58.8°
- Nearest star
- Alp Cir · 54 ly
Visible from everywhere south of about 25°N.
When and where to look for Circinus
Circinus crosses the meridian — its highest point in the sky — at local midnight around April, which makes the months from March to May the easiest time to find it in the evening. It spans declinations -65.0° to -58.8°, so visible from everywhere south of about 25°N.
The quickest way to find it is to open the live AR sky map and point your phone at the sky — if Circinus is above your horizon right now, its figure is drawn in the position it genuinely occupies above you.
Brightest stars in Circinus
| Star | Mag | Type | Distance |
|---|---|---|---|
| Alp Cir | 3.18 | F1Vp | 54 ly |
| Bet Cir | 4.07 | A3V | 99.7 ly |
| Gam Cir | 4.48 | B5III + F8 | 448.6 ly |
| Eps Cir | 4.85 | K2.5III | 407.7 ly |
| Del Cir | 5.04 | O8.5V | — |
| The Cir | 5.08 | B4Vnp | 1,510 ly |
Magnitude runs backwards: lower numbers are brighter, and anything below about 6.5 is beyond the naked eye under a dark sky.
What Circinus is made of
The catalogue lists 40 stars within Circinus, of which 40 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 Alp Cir at 54 light years. The most distant is HD 125835 at roughly 2,026 light years — stars that appear side by side here are nothing of the sort.