M16 - Eagle Nebula

The Eagle Nebula (also known as M16 or NGC 6611) is a large H II region visible in the constellation of Serpens Cauda; it consists of a young open star cluster associated with an emission nebula of ionised hydrogen, catalogued as IC 4703. Its distance has always been relatively uncertain, but a value of about 5,700 light-years from Earth is generally accepted, placing it in the middle of the Sagittarius Arm. It contains some very well-known features, such as the Pillars of Creation, long columns of dark gas shaped by the stellar wind of the central cluster's stars, which also give the nebula its name because of their shape. Young stellar objects are found within them, evidence that star-formation processes are still under way, though it is unclear whether the stellar wind of nearby stars favours or hinders them. The cluster is made up of a large number of very hot, bright blue supergiants, typically only 2-3 million years old — less than a thousandth of the age of our Sun; the cluster's brightest star has magnitude 8.24, clearly visible even with binoculars. The nebula has been known since the 18th century and is one of the most famous objects in the Messier Catalogue: it shows up easily in photographs and is therefore an excellent subject for amateur astrophotography enthusiasts.