star clusters are so dense, why don't they collapse in on themselves from their own gravity?
And yet, perhaps partly because of this, M2 looks more like a globular
cluster and is a little more obvious in 10x50 binoculars than M15.
Radial chains are common in globulars
, but the allure of M30 is that they trend strikingly in one direction.
This longer wavelength, invisible to the human eye, has a second benefit especially germane to assisted observing of globulars
clusters typically contain tens to hundreds of thousands of fiery suns.
clusters, the brightest stars have about the same luminosity, but their apparent magnitude largely depends on distance.
However, this globular
displays one especially interesting feature--it's bisected by a north-south band of relatively bright stars.
The closest confirmed globular
cluster is Messier 4, just 7,000 light-years from Earth.
Hercules is the constellation that spells "summer" for me, and Messier 13, the Great Globular
Star Cluster, is undoubtedly Here's premiere deep-sky object.
The summer sky is where you'll find M22--and almost all the other bright globular
star clusters visible from the Northern Hemisphere.
A group of globulars
lies near M31's core: relatively easy G235 and G222; fairly difficult G230; and difficult G229, G257, G205, and G217.
Of all the various types of deep-sky objects, globular
clusters routinely give beginning binocular observers the most unexpected difficulty.