Celestial hemisphere:  Southern  ·  Constellation: Scorpius (Sco)  ·  Contains:  B287  ·  M 7  ·  NGC 6444  ·  NGC 6453  ·  NGC 6475  ·  PK355-04.1  ·  PK355-04.2  ·  PK356-04.1  ·  Ptolemy cluster
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M7 Ptolemy Cluster in Scorpius, Sigga
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M7 Ptolemy Cluster in Scorpius

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M7 Ptolemy Cluster in Scorpius, Sigga
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M7 Ptolemy Cluster in Scorpius

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Description

Messier 7 or M7, also designated NGC 6475 and sometimes known as the Ptolemy Cluster,[4] 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.

In 1764, French astronomer Charles Messier catalogued the cluster as the seventh member in his list of comet-like objects. English astronomer John Herschel described it as "coarsely scattered clusters of stars".

Telescopic observations of the cluster reveal about 80 stars within a field of view of 1.3° across. At the cluster's estimated distance of 980 light years this corresponds to an actual diameter of 25 light years. The tidal radius of the cluster is 40.1 ly (12.3 pc) and it has a combined mass of about 735 times the mass of the Sun. The age of the cluster is around 200[2] million years while the brightest member star is of magnitude 5.6.

--Wikipedia

More:

Messier7 - Wikipedia

Messier7 - Astropixels.com

Messier7 - SED

This is image #12 in long term project to photograph the complete Messier catalog. While I still have a long way to go I am pleased with how images have progressively improved. Thanks to all who offered advice.

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M7 Ptolemy Cluster in Scorpius, Sigga