M7

M7Messier 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.

Image Credit: ESO

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