Winter and the Pleiades
The Pleiades are an impressive sight with any or no optical aid. How many stars can you see with your naked eye?
Courtesy Akira Fujii.
The best-known deep-sky object is the
Pleiades or Seven Sisters (M45). This star cluster rests on the shoulders of Taurus, the Bull,
and is easily visible with the naked eye. Most people can see 6 to 10 "Pleiads" with the brightest arranged in the shape of a tiny dipper. The view through binoculars is stunning! You'll see a few dozen stars through 7 x 50 binoculars. Larger binoculars and small telescopes can show more than 100. The Pleiades are wrapped in a faint nebulosity that is a challenge to observe. The brightest part extends southward from the star that marks the lower-left corner of the dipper's bowl.
Perseus is home to some wonderful star clusters. One of the best binocular targets among them is the Alpha Persei association (Melotte 20). This breathtaking group consists of about 20 fairly bright stars and dozens of fainter ones. They are scattered across 3° of sky mostly to the lower right of the group's brightest member, Mirphak (α).
The Double Cluster is easy to find; it's visible toward the bottom of this photograph. Click on the image for a closeup of the region that includes the Double Cluster.
Courtesy Akira Fujii.
To the lower left of Cassiopeia's distinctive
W-shape, beneath the stars Delta (δ) and Epsilon (ε) Cas, is another visual treat when seen in binoculars or a small telescope — the
Double Cluster in Perseus. Recent studies have revealed that they really are twins — both clusters (also known as NGC 869 and 884) are about 13 million years old and 7,300 light-years away. They're barely visible to the naked eye, but if you're observing on a moonless night, your binoculars will show the Double Cluster as side-by-side clumps of stars imbedded in the thin winter Milky Way.
