One of the star clusters that might "eye catching" in the clear night sky. In astronomy, the Pleiades (Messier object 45) is an open star cluster in the constellation of Taurus, the star cluster most obvious to the naked eye, and the one that is closest to the Earth. The cluster is dominated by hot blue stars that formed less than 100 million years ago. Dust that forms a reflective nebula around the bright stars originally thought to be the remains of the constituent, but is now known that these nebulae interstellar medium dust cloud just happened to be crossed by the group. Astronomers estimate that the cluster will last up to approximately 250 million years, after which the group will be scattered due to gravitational interactions with its neighboring objects.
Perhaps the most famous star cluster on the sky, the Pleiades star cluster can be seen without binoculars from even the depths of a city full of light and polluted. Also known as the Seven Sisters and M45, the Pleiades star cluster is one of the nearest open clusters and bright. Pleiades star cluster containing over 3000 stars, is about 400 light-years away, and only 13 light years wide. Quite clear in the photo above are blue reflection nebulae that surround the brighter star clusters. Low-mass brown dwarf stars and dim also been found in the Pleiades. Diffraction stands out due to the telescope that took the picture itself, may interfere with or may actually increase the beauty of art, depending on your viewpoint.
Image Credit: Robert Gendler
In the Telescope: Some 40 to 50 stars may be visible, but the group is so large that even at low power you won’t be able to fit them all into the field of view at any one time. Using larger telescopes (6" or more) under very dark skies you can begin to see faint wisps of nebular gas near some of the stars. (However, if you see “nebulosity” around all the brightest stars, that just means you’ve got dew on your lenses!) Look especially south of the star named Merope, the southernmost of the four stars that make up the “bowl” shape.
The Pleiades are easy to find, and there’s something worth looking at in any sized telescope. Binoculars are best at getting across the richness of the cluster, while very dark skies and a much bigger telescope can allow you to see the nebulosity around the stars. In some ways a 2" to 3" telescope is just the wrong size to M45 at low power The Pleiades 41 really appreciate this cluster; nonetheless, seeing so many bright blue stars in one place, especially against the contrast of a very dark sky, can be quite impressive. What You’re Looking At: Over 200 stars have been counted in this cluster; it lies about 400 light years away from us. Most of the stars fit within an area 8 light years across, but the outer reaches of the cluster extend across 30 light years. The stars visible in a small telescope are all young blue stars, spectral class B and A, surrounded in many cases by the last wisps of the gas clouds from which they were formed. Because this gas is still present, and none of the bright stars have evolved into red giants, it is widely believed that these stars are quite young, perhaps less than 50 million years old, only 1% of the age of our Sun.