In this image, the cluster is almost lost against the background stars. The cluster is the group of moderately brighter stars located in the center of the photo. When viewed by eye in most telescopes, the cluster stands out better since our eyes cannot pick up the fainter stars as easily as a camera can. This causes the brigher stars to appear more prominent. But in a long exposure photograph like this one, so many more stars become visible that clusters like these blend in a lot more.
