The Pleiades star cluster
by Mike Palermiti
Open clusters are younger, less massive, and more scattered; because of their lower mass they tend to "evaporate" over time, losing stars until they eventually disappear. Both types of clusters make for splendid viewing through telescopes of all sizes. This photo of the Pleiades, a beautiful sight in binoculars, was made through a telephoto lens on a clock-driven mount that compensates for Earth's rotation, keeping the object centered in the field of view during a long exposure.