The Southern Cross: Navigating the Southern Sky
If you have ever stood beneath the sky south of the equator, you may have noticed a small, bright cluster of stars shaped like a kite. That is the Southern Cross, the most famous signpost of the southern heavens and a navigator's best friend for thousands of years. Compact yet unmistakable, it points the way south the way Polaris guides the north.
What the Southern Cross actually is
The Southern Cross is the constellation Crux, the smallest of all 88 constellations but one of the brightest. Its four main stars form a slightly lopsided cross, with a fifth fainter star tucked inside the frame. Two nearby brilliant stars, Alpha and Beta Centauri, are often called the Pointers because they sit just beside it and help you tell the real Cross from look-alikes.
Crux sits in a rich part of the Milky Way, so on a dark night you will see it embedded in a glowing river of stars. Nearby lurks the Coalsack, a dark nebula that looks like a hole punched in the bright band behind it.
How to find the Southern Cross
From the southern hemisphere, the Cross is visible year-round and never sets across much of Australia, southern Africa and South America. The trick is separating it from the larger, fainter "False Cross" a little to the west. The Pointers settle the matter every time.
- Face roughly south and look for a tight, kite-shaped group of four bright stars.
- Find the two bright Pointer stars beside it; they always flank the true Cross.
- Get away from city glow so the surrounding Milky Way stands out.
- Let your eyes adjust for fifteen to twenty minutes before searching.
Using it to find south
The Cross is a built-in compass. Trace an imaginary line down the long axis of the Cross and extend it about four and a half times its length. Drop straight down to the horizon from that point, and you are looking very nearly due south, the same job Polaris does up north. If you are still learning the sky, our guide to stargazing for beginners will help you get comfortable, and how to find the North Star shows the northern mirror of this trick.
Ready to spot it for yourself? Open the Starly sky map, set your location, and watch the Southern Cross light up exactly where it hangs above you tonight.
Open the sky map with Crux highlighted and use it to point the way to true south.
Frequently asked questions
Can you see the Southern Cross from the northern hemisphere?
Only from far southern latitudes near the equator and below; across most of the northern hemisphere it stays hidden under the southern horizon.
How do you tell the Southern Cross from the False Cross?
The two bright Pointer stars, Alpha and Beta Centauri, sit beside the true Cross. The larger, fainter False Cross has no such pair, so the Pointers settle it every time.