Wide-field view of the sky around the star cluster Westerlund 1

This wide-field view from the Digitized Sky Survey 2 is centred on the star cluster Westerlund 1 in the constellation of Ara (The Altar). This cluster appears as a dense orange clump at the centre of the picture. It is very young and contains massive and brilliant hot blue stars, but their light is much reduced and reddened by a dense cloud of dust between the cluster and the Earth. This is a very rich part of the Milky Way and huge numbers of stars, along with many dust clouds, can be seen.