M55 is a large and lovely globular cluster of around 100,000 stars in the constellation Sagittarius.

Clusters like M55 roam the halo of galaxies. This one is in our own Milky Way galaxy at a distance of 20,000 light years. All these stars are bound together by gravitation.

This view spans about 100 light years across (600 million million miles)

Photo Credit: B.J.Mochejska, J.Kaluzny(CAMK), 1m Swope Telescope)