Acrux: how to find it and when to see it
Acrux ranks 13th of the 74 bright stars on our list, at magnitude 0.77, in the constellation Crux.
You can see it from anywhere south of 27° N, and it's highest in the evening sky in May.
Acrux at a glance
- Constellation
- Crux
- Magnitude
- 0.77
- Rank on our list
- 13 of 74
- Hemisphere
- Southern
- Right ascension
- 12 h 27 min
- Declination
- 63.1° south
- Visible from
- south of 27° N
- Never sets
- south of 27° S
- Best evening
- 13 May
- Name from
- Modern
Where Acrux is in the sky
Acrux sits 63.1° south of the celestial equator, the line in the sky directly above Earth's equator, so it's in the southern half of the sky. Its right ascension is 12 h 27 min.
Right ascension works like longitude on the sky. It's counted in hours, and about one hour of it turns past you each hour of the night.
When and where to see Acrux
From the northern hemisphere
From 40° N, the latitude of New York, Madrid and Beijing, Acrux never rises above the horizon. You need to be south of 27° N to see it.
From the southern hemisphere
From 34° S, the latitude of Sydney, Cape Town and Buenos Aires, Acrux never sets: it circles the pole all night and climbs to 61° above the horizon in the south.
It's in the evening sky from December to September, and it's highest in the evening around 13 May, in autumn.
How high Acrux climbs from each latitude
The evening is about 9 pm local time, or 10 pm in summer time, and later when the sky is still too bright. A star counts as in the evening sky when it's at least 10° above the horizon.
| Latitude | Visibility | Highest point | Evening sky |
|---|---|---|---|
| 60° N | Never rises | Below the horizon | None |
| 50° N | Never rises | Below the horizon | None |
| 40° N | Never rises | Below the horizon | None |
| 30° N | Never rises | Below the horizon | None |
| 20° N | Rises and sets | 7° in the south | None |
| Equator | Rises and sets | 27° in the south | Mar to Jul |
| 20° S | Rises and sets | 47° in the south | Feb to Aug |
| 34° S | Never sets | 61° in the south | Dec to Sept |
| 45° S | Never sets | 72° in the south | All year |
What the name Acrux means
Acrux is a short form of Alpha Crucis, its catalogue name as the brightest star of Crux, the Southern Cross.
Keep the sky of a night that matters
Our star maps show the stars above any place, at the minute you choose, with the constellation lines drawn in. If Acrux was above the horizon that night, it's on your map, and we print it on museum-grade paper.
Questions about Acrux
Acrux is in Crux. It sits 63.1° south of the celestial equator, at a right ascension of 12 h 27 min.
Acrux is highest in the evening sky around 13 May. That's spring in the northern hemisphere and autumn in the southern hemisphere.
Yes, from anywhere south of 27° N. From 40° N, it never rises, so you need to be further south.
Acrux has a magnitude of 0.77, which ranks it 13th of the 74 bright stars on our list. Sirius looks about 7.7 times brighter.
Acrux is a short form of Alpha Crucis, its catalogue name as the brightest star of Crux, the Southern Cross.