Omega Centauri is the brightest globular star cluster visible from Earth. It’s in the southern sky and climbs into our northern hemisphere skies on spring evenings.
Clusters Nebulae Galaxies
The Trifid Nebula (Messier 20) is one of the many binocular treasures in the summer Milky Way. Its name means “divided into three lobes,” but you’ll probably need a telescope to see why. On a dark, moonless night, you can star-hop upward from the spout of the Teapot in Sagittarius to the Lagoon Nebula (Messier 8). In the same binocular field, look for the smaller and fainter Trifid Nebula as a fuzzy patch above the Lagoon.
The Lagoon Nebula is the largest and brightest of a number of nebulosities in and around Sagittarius.
Although long-exposure photographs show the Triangulum galaxy (Messier 33) in a beautiful pinwheel shape, this face-on spiral galaxy looks relatively lackluster in binoculars or even the telescope. The Triangulum galaxy has a low surface brightness that makes this faint object a major challenge, with or without binoculars.
Barely visible to the unaided eye on a dark, moonless night, the Eagle Nebula (Messier 16) and Omega Nebula (Messier 17) are best seen through binoculars, or low power in a telescope. These two closely-knit patches of light readily fit within the same binocular field. Star-hop to them from the Teapot in Sagittarius.
Outside on a dark summer night, looking edgewise into our galaxy’s disk, you’ll notice a long, dark lane dividing the bright starry band of the Milky Way. This is the Great Rift.
Between the star Regulus in Leo and the stars Castor and Pollux in Gemini, you might notice a smudge – really a cluster of stars – called the Beehive.
If you’ve never found a deep-sky object on your own before, M4 is a grand place to start. The M4 star cluster is easy to find, because it’s right next to Antares, the brightest star in the constellation Scorpius the Scorpion. This is not an open star cluster or loose collection of fairly young stars. Instead, it’s a globular star cluster, a symmetrical grouping of some of the galaxy’s oldest stars.
The Great Hercules cluster (Messier 13) is considered to be the finest globular cluster in the northern half of the heavens. It’s found in a star pattern called the Keystone – a lopsided square within the constellation Hercules – between the two brightest stars of summer, Vega and Arcturus.