The smallest constellation of all, better known as the Southern Cross. Its distinctive cross-shape is marked by four stars: Acrux (Alpha Crucis); Mimosa (Beta Crucis); Gacrux (Gamma Crucis); and the faintest of the four, Delta Crucis, magnitude 2.8. Mu Crucis is a wide double of magnitudes 4.0 and 5.2. NGC 4755 is a sparkling open cluster known as the Jewel Box or the Kappa Crucis Cluster. Crux lies in a rich part of the Milky Way, part of which is blotted out by the dark Coalsack nebula.