Sirius, the brightest star in the night sky, highlights this view of the front of Canis Major, the big dog. The constellation is low in the south as night falls in March, and is easy to pick out even from light-polluted cities. The star Mirzam shines to the right of Sirius, with the star cluster M41 below Sirius, near the bottom of the image. Under dark skies, the cluster is just visible to the unaided eye, although you'll need binoculars to find it under brighter skies. [Christos Doudoulakis/Wikimedia]
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Milky Way Clusters
If you have access to a dark skywatching site, far from the glow of city lights, this is a great evening to look at the Milky Way. It arcs high overhead as darkness falls, so it’s quite a sight. And the Moon doesn’t rise until the wee hours of the morning, so it won’t spoil the show.
That faint, milky band of light outlines the disk of the Milky Way galaxy. It’s the combined glow of millions of stars. The stars are so far and faint that we can’t see them individually with our eyes alone.
If you look carefully, though, you’ll see some slightly brighter spots within the Milky Way. Many of those are star clusters — big groups of stars that move through space together. They congregate in the band of the Milky Way because they, too, belong to the galaxy’s disk.
One of the easiest to spot is Messier 41. That’s because it’s close below Sirius, the brightest star in the night sky, which is in the south at nightfall. M41 is just bright enough to see with the eye alone, as a hazy smudge of light. But binoculars will reveal some of the cluster’s individual stars.
A string of Messier clusters stretches high across the sky: M35, 36, 37, and 38. They line up to the left of Capella, a brilliant yellow-orange star that’s high in the northwest. They’re fainter than M41, but all of them are good targets for binoculars — vast families of stars glowing within an even bigger family: our home galaxy, the Milky Way.