Crux (Southern Cross)
What is Crux (Southern Cross)?
Constellations· Southern skies (not visible from Korea) · smallest of the 88 · pointer to the south pole. Smallest of the 88 constellations, yet the emblem of the southern sky. With no southern pole star, navigators extend the long axis 4.5× to find the pole — the stars on the flags of Australia and New Zealand.
📍 Visible from where you are right now — computed in your browser
bearing · altitude · rise time · best time tonight
Where Crux (Southern Cross) is in your sky right now: https://nowsky.org/solar/sky?sel=con:Crux — location and time set automatically, no login.
Stars of the figure
| Star | Magnitude |
|---|---|
| Acrux | 0.8 |
| Mimosa | 1.3 |
| Gacrux | 1.6 |
The 3 brightest of the 4 stars used in the figure (2 lines). Lower magnitude means brighter.
Deep-sky objects near this constellation
Constellation basics
| Season | southern skies |
|---|---|
| Size | smallest of the 88 |
| Role | guide to the south celestial pole |
Figures are representative approximations. Source: compiled from NASA and IAU public data.
Frequently asked
- When can I see Crux (Southern Cross)?
- southern skies.
- What is the brightest star in Crux (Southern Cross)?
- Acrux, magnitude 0.8.
- In one line, what is Crux (Southern Cross)?
- Constellations — Smallest of the 88 constellations, yet the emblem of the southern sky.
- Where is Crux (Southern Cross) in the sky right now?
- Open the sky view for your location and time and it shows the position in the sky right now.
Why the flags show different numbers of stars
Several national flags carry the Southern Cross, but not with the same number of stars. Australia shows five, New Zealand four, Brazil, Papua New Guinea and Samoa five. New Zealand drew only the four bright stars of the cross, while Australia and Brazil added the fifth star inside it, Epsilon Crucis. At 4th magnitude it shows only under a dark sky, and the flags reveal which country took a darker sky as its standard.
The sizes of the four stars on the flags also follow their real brightness: the Australian flag gives Acrux, Mimosa and Gacrux seven points and the faintest, Delta, a small five-pointed star. Gacrux is the only red giant of the four, a near star 88 light-years away, while the other three are blue stars more than 300 light-years off, so a flag that showed colour would redden only the top of the cross. The designs record how closely people of the south have watched these stars.
The constellation in depth
Crux is the smallest of the 88 constellations and the emblem of the southern hemisphere — its four bright stars fly on the flags of Australia, New Zealand, Brazil and more.
With no bright southern pole star, sailors extend the cross's long axis 4.5× to find the celestial pole. The Coalsack dark nebula and the Jewel Box cluster crowd beside it.
Precession once lifted it into Mediterranean skies in Greek antiquity; today you must travel below ~25°N — from Korea, this is a constellation worth a journey.
Beside the Cross hangs a naked-eye hole in the Milky Way — the Coalsack dark nebula, a dust cloud silhouetted against the galaxy's glow. Aboriginal Australian cultures drew an 'emu in the sky' from such darkness rather than from stars. Extend the Cross's long axis 4.5 times and you reach the south celestial pole — the southern hemisphere's compass.
Related
Figures are representative approximations. Simulated positions use J2000 mean elements.