Southern cross (Crux Australis) constellation (lower centre) in the night sky. The southern cross is the smallest constellation in the sky, visible in the lower northern and southern hemispheres. Its characteristic shape is made up of four stars. At the top is Gamma (centre). To the left of and below Gamma is Mimosa. The bottom of the cross is marked by the bright double star Acrux (Alpha Crucis). Delta, above and to the right of Acrux, completes the cross. Epsilon is seen between Acrux and Delta here. The southern cross was an important inspiration for Catholic sailors in the 15th and 16th centuries as they extended the known world. Photographed in Cuba.