The Crescent Nebula is a strange alien looking rippled mass of dust and light in the heart of the constellation Cygnus, The Swan, flying along The Milky Way. It is an emission nebula about five thousand light years away lit by its bright central star. Whilst called The Crescent Nebula, it is hard to look at this object and not be reminded of a human brain, a comment made regularly about this nebula during the various exhibitions of In The Marlborough Night Garden.

This image uses narrowband filters to separate the hydrogen alpha light (Hα) and the doubly ionised oxygen light (OIII) to reveal the intricate detail of the nebula. The Hα is visible as the red coloured structures, while the OIII shows as the green-blue coloured outer shell of the nebula.

The Crescent Nebula is formed by the fast stellar wind from the bright Wolf-Rayet star (WR 136) at the centre of the nebula colliding with and energising the slower moving wind ejected by the star when it became a red giant around 300,000 years ago. With its exterior stripped and its inner helium layers laid bare, the massive star became unstable. The resulting instability led to the Wolf-Rayet phase of prodigious mass loss from the star’s surface. The mass loss occurs at a furious pace in the form of a powerful, high energy stellar wind travelling at speeds up to 3,000 km/s (about 6 million miles per hour).

WR 136 is shedding its outer envelope at a tremendous rate, ejecting the equivalent of the Sun’s mass every 10,000 years. The star is approximately 15 times more massive than our sun, over 250,000 times brighter and is expected to finish its stellar life by exploding as a supernova in around 100,000 years.