M67

An LRGB image of the open cluster M67.  

I selected 300s sub exposures, down from my normal 600s, to avoid excessive star bloat. To maximize star colour, I also decided to process the image using two different DDP stretches of the Lum, a high one, targeting the dim objects and one low, targeting the bright stars. The result image was then blended together in PS with an appropriate mask. 

The cluster is unusual in that it is incredible ancient (c3billion years), somehow, it has resisted the gravitational forces which tend to disperse most open clusters over several hundred million years. As a consequence, M67 has more yellow/red and less blue stars than younger open clusters.