M80 is in the constellation Scorpius between the stars α Scorpii (Antares) and β Scorpii in a part of the Milky Way rich in nebulae. When viewed with a modest amateur telescope (like mine), it appears as a mottled ball of light. This Hubble image shows more detail. M80 is roughly 95 light-years in diameter. It contains several hundred thousand stars, making it one of the more densely populated globular clusters in the galaxy.
M80 contains a fair number of blue stragglers, stars that appear to be much younger than the cluster itself. Astronomers believe that these stars lost part of their outer layers during close encounters with other cluster members or as the result of collisions between stars in the tightly packed cluster. Images from Hubble show regions with very high blue straggler densities which suggests that the center of the cluster probably has a very high capture and collision rate.
Messier 7 or M7, sometimes known as Ptolemy’s Cluster, is an open cluster of stars in the constellation of Scorpius. The cluster is easily detectable with the naked eye, close to the “stinger” of Scorpius.
M7 has been known since antiquity; it was first recorded by the 1st-century Greek-Roman astronomer Ptolemy, who described it as a nebula in AD 130. Italian astronomer Giovanni Batista Hodierna observed it in the mid 17th-century and counted 30 stars in it. In 1764, French astronomer Charles Messier catalogued the cluster as the seventh member in his list of comet-like objects. This image was recently taken by the 2.2-metre ESO telescope in Chile.
This video pans across the region around star cluster NGC 6604. It’s derived from an image taken by the Wide Field Imager attached to the MPG/ESO 2.2-metre telescope in Chile. The picture also shows the cluster’s associated nebula, a cloud of glowing hydrogen gas that is called Sh2-54.
Using data from the VISTA infrared survey telescope at ESO’s Paranal Observatory, astronomers have discovered new open clusters hidden by the dust in the Milky Way. Thirty of these clusters are shown in this mosaic. These objects were invisible to previous surveys, but they visible using the sensitive infrared detectors of the world’s largest survey telescope which can see through the dust. The false color images are made using different wavelengths of infrared light. Click the image to embiggen it.
M15 (in the constellation of Pegasus) is an easy target for backyard astronomers. On a clear night, it’s visible as fuzzy spot with a decent pair of binoculars. A 150-mm or larger telescope will reveal some individual stars in the cluster. Here’s what it looks like using Hubble.
The cluster is estimated to be one of the oldest known, about 12 billion years old. It contains over 100 variable stars, eight known pulsars, and a double neutron star. Its central region has undergone core collapse and may contain a black hole.