Acrux
Where is Acrux?
Below the horizon from London all the time in Crux.
- Rises
- Never
- Highest
- —
- Sets
- —
- Best after dark
- —
Can I see Acrux tonight?
Acrux never rises from London: it is too far south in the sky for this latitude.
This is position and timing only: clouds, haze and light pollution aren’t included.
What does Acrux look like?
Acrux looks blue-white to the eye. Its spectral type is B0.5IV + B1V: hot blue-white subgiant (much hotter than the Sun).
Eyes
A bright blue-white star at the bottom of the Southern Cross.
Binoculars
The whole Cross fits in the field, along with the dark Coalsack Nebula beside it.
Telescope
Even a small telescope splits Acrux into two bright blue-white stars, one of the finest doubles in the southern sky.
About Acrux
Acrux is the brightest star in the Southern Cross, at the foot of the cross. To the eye it is one star, but a small telescope shows two blue-white stars, and the brighter one is itself a close pair.
It is about 320 light-years away. The Southern Cross appears on the flags of Australia, New Zealand, Brazil, Papua New Guinea and Samoa.
The Southern Cross is the smallest of the 88 constellations. It was once considered part of Centaurus and was recognized as a separate constellation by European navigators in the 16th century.
Acrux is around 320 light-years away, so its light left it in the 1700s. Its brightest components are massive, hot stars that will end their lives as supernovae.
Right beside the Cross lies the Coalsack, a dark cloud of dust that blocks the light of the Milky Way behind it. It is easy to see with the naked eye from dark southern skies.
Acrux in Crux
Questions
How do I use the Southern Cross to find south?
Is Acrux a double star?
Sources: SkyMate; Wikidata (CC0). Positions computed for your place and time with astronomy-engine. Data & Licences