Crux

Crux, the Southern Cross, is the smallest constellation in the sky yet one of the most distinctive, at least to those of us who live in the southern hemisphere. It was once part of Centaurus, where the bright stars Acrux and Mimosa could easily be imagined as the rear hooves of the rearing mythical centaur. However, when Christian sailors began to explore southwards in the 16th century, this memorable asterism took on a new significance.

Alongside the Southern Cross is a very distinctive dark shape known as the Coalsack, much used by southern hemisphere astronomers as an indicator of a dark sky. The Southern Cross is visible from most of Australia at some time every night of the year. Its long axis points towards the south celestial pole, so the Cross itself acts as a very convenient circumpolar clock, compass and calendar.

Credit: Akira Fujii/David Malin Images
Post by David Malin, From Earth to the Universe team.