Explanation:
M7 is one of the most prominent
open clusters
of stars on the sky.
The cluster, dominated by bright blue
stars,
can be seen with the naked eye in a dark sky
in the tail of the constellation of the Scorpion (Scorpius).
M7 contains about 100 stars in total, is about
200 million years old,
spans 25
light-years across, and lies about 1000 light-years away.
The above deep exposure was taken last month over several nights from
Yalbraith,
NSW,
Australia.
The M7 star cluster
has been known since ancient times, being noted by
Ptolemy in the year
130 AD.
Also visible are a
dark dust cloud
and literally millions of unrelated stars
towards the Galactic center.
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