Map of the Universe

Ptolemy Cluster

Open star cluster · Open star cluster in the constellation of Scorpius

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Ptolemy Cluster
Picture: Credit: ESO, CC BY 3.0, via Wikimedia Commons.

About Ptolemy Cluster

Ptolemy Cluster is about 900 light-years from the Sun, so the light we see from it left about 900 years ago.

It is 26,101 light-years from the centre of the Milky Way.

The map lists it as an open star cluster and shows it among the stars around the Sun, drawn on the plane of the Milky Way.

Key numbers

Distance900 light-years (276 pc)
Distance from the Galactic centre26,101 light-years
Galactic coordinatesl = 355.84°, b = -4.53°
Member stars (Gaia)1,427
Age171 million years
Mass (observed)2,393 solar masses
Half-member radius10.6 light-years

Data: Hunt & Reffert 2024.

Where it is

Its place in the universe, from the inside out: Milky Way › Local Group › Virgo Supercluster › Laniakea Supercluster › Observable universe.

Zoom out to see it in context: 1,000 light-years, a view about 2,400 light-years across.

From Wikipedia

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.

Excerpt from the Wikipedia article Messier 7, licensed CC BY-SA 4.0.

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