Messier 7 or M7, also designated NGC 6475 and 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. With a declination of −34.8°, it is the southernmost Messier object.
M7 was first recorded by the 2nd-century Greek-Roman astronomer Ptolemy, who described it as a nebula in 130 AD. Italian astronomer Giovanni Batista Hodierna observed it before 1654 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. English astronomer John Herschel described it as “coarsely scattered clusters of stars”.
Object Designations: M7, NGC 6475
Also known as: Ptolemy’s Cluster
Constellation: Scorpius
Object Type: Open Cluster
Distance: 25 light-years away
Magnitude: 3.3
Discovery: 2nd-century Greek-Roman astronomer Ptolemy
This final image is:
10 – 30 second subs at 100 gain – no filter abouy 5 minutes of integration
I processed the images using Pixinsight using:
AutomaticBackgroundExtractor
BlurExterminator
NoiseExterminator
EZProcessing Suite Softstretch (img version 1)
