The Double Cluster

Date: March 1-15
Time: 7:30 pm, one hour after sunset
Place: the northwestern sky

During the first half of March the Moon will be absent from the early evening sky. Without its glaring light, the Milky Way comes into easy view. The Milky Way is that cloud-like structure you sometimes see arching across the sky. In 1610, Galileo discovered it was composed of myriad distant stars, so closely packed that their light was smeared into a continuous glowing band.

There are so many stars in this part of the sky that you can find many interesting astronomical objects just by random scanning with binoculars. One of the most beautiful is the Double Cluster (see inset). Each of these clusters contains over a hundred stars. In dark skies they can be seen with the unaided eye. Through even small binoculars they are truly spectacular.

The Double Cluster is in the faint constellation Perseus, but nearby Cassiopeia (The “W”) makes it easy to locate. Look slightly above Cassiopeia for a brighter patch of  light. These clusters are about 7000 light years distant and contain mostly young blue-white stars. Interspersed are a few older, cooler stars that look distinctly orange-red and provide a nice visual contrast.

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