The Calabash Nebula and its surroundings (ground-based image)

This image is from the Digitized Sky Survey II and shows half a degree of sky centred on the Calabash Nebula (indicated by the circle) also known as the Rotten Egg Nebula. The nebula is lying in the star cluster Messier 46 - seen in the lower right corner of the image. The astronomers are investi...