Globular Clusters

Star clusters are groups of stars that have a common origin and are gravitationally bound. There are two types of star clusters; Globular Clusters and Open clusters.

Globular Clusters are tightly bound groupings of hundred of thousands of old stars located in the galactic halo and are remnants of the formation of our galaxy.

Open Clusters are relatively young associations containing only a few hundred loosely bound stars and are located in the spiral arms of our galaxy.

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Called the “Great Cluster”, M13 is regarded as the finest globular cluster viewable from the northern hemisphere. It contains over 100,000 stars packed into a spherical shape 150 LY in diameter.

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M15 is located 33,600 LY distant with over 100,000 stars and a luminosity 360,000 times that of the Sun. It is 175 LY in diameter and has an apparent magnitude of 6.2.

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The globular cluster M22 is relatively close at 10,600 LY and contains some 70,000 stars

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NGC 6522 & 6528 are Globular Clusters located near the central bulge of our Milky Way Galaxy some 25,700 light years distant. The great density of stars near the center of our galaxy is clearly evident and this particular area is notable for the relative absence of obscuring clouds of interstellar dust normally found in the central regions of galactic nuclei.
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Mayall II is an example of a globular cluster that has been observed in the halo of our closest galactic neighbor – M31 “The Andromeda Galaxy”. Though it appears to be a star-like object in my modest telescope, the inset image taken by the Hubble Space Telescope reveals its globular nature.
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