This is the close-up of the previous picture. The prominent star cluster M35, which is visible in clear nights even to the naked eye, is obviously an irregular association of young stars ready to drift apart into space. But what about the smaller brother? NGC 2158 resembles a globular cluster, but the impression is misleading. The cluster is just so far away and the structure so condensed that plenty of astronomers miscategorized the object. Modern spectroscopy confirms that NGC 2158 is considerably old for an open cluster, but far too young to be a globular.
The distance is more than 15 000 light years, more than 5 times the distance of M35. So the apparent vicinity of these two clusters is just an illusion. The light has to pass through plenty of dust along the path between the cluster and earth, ahich explains the reddish tone in the star colours.
Don't forget to watch the high resolution picture!