Best Star Clusters to Observe
Beautiful Stellar Groupings that Don't Require a Telescope
Oct 26, 2009
By late fall, all three of the best naked-eye star clusters are above the east-southeastern horizon in the evening. The Hyades, Pleiades, and Beehive Clusters are a good collection of objects to compare their views with through a telescope, binoculars, and with the eyes alone.
Observing the Hyades Cluster
The Hyades Cluster is also known as Melotte 25 or the head of Taurus the Bull. This V-shaped grouping of stars appears the largest in the sky compared to the other two listed here, spanning about five degrees across. The Hyades composes the main portion of the constellation Taurus. The fourteenth brightest star in the sky, Aldebaran, lies at the edge of this cluster but is not actually a physical member of the Hyades. The red giant Aldebaran is much nearer at 60 light-years.
This cluster is easy to see without optical aid. Using binoculars or a telescope will limit the field of view and exclude some of the members of this cluster, but it will also reveal more of the 200-plus members of the cluster. At only 150 light-years away, it is the closest open cluster to Earth. The cluster is about 790 million years old. The Beehive Cluster is a similar age and the direction of movement of both of these suggests that the two clusters had a common origin.
Observing the Pleiades Cluster
The Pleiades Cluster is also known as M45 or the Seven Sisters. This cluster is also in the constellation Taurus the Bull, found above the Hyades. Despite its nickname, only six stars can usually be seen without optical aid. Using binoculars might cut out some members of the cluster, but it will reveal hundreds more stars in the grouping. Most telescopes' fields of view are too small to show the entire cluster at once; naked eye or binoculars give the best view. However, a telescope can help observers to spot the Merope Nebula, which is associated with the cluster.
The Pleiades Cluster lies about 380 light-years from Earth and is approximately 100 million years old.
Observing the Beehive Cluster
The Beehive Cluster is also known as M44 or Praesepe ("the manger"). This cluster marks the center of the constellation Cancer the Crab, which lies on the other side of Gemini from Taurus. Cancer rises about four hours after Taurus.
The Beehive Cluster shines at about magnitude 3.7, therefore it is still easy to find without optical aid, but it is much smaller is size than the Hyades and a bit smaller and dimmer than the Pleiades. Observers can use binoculars or a telescope to spot a couple hundred of the approximately 350 members of this cluster. The Beehive is about 577 light-years away from Earth and its stars are approximately 730 million years old.
Fall contains three of the best star clusters in the Northern Hemisphere and no equipment is needed to see these beauties.
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