Open star cluster
Ptolemy's Cluster
Also M7 · NGC 6475
A bright open cluster near the sting of Scorpius, easy to see with the naked eye.
Measured
- Distance
- about 900 light-years (published estimates 900–913)
- Size
- about 50 light-years across (approximate)
- Constellation
- Scorpius
- Position (J2000)
- RA 17h 53m 51s, Dec −34.79°
How far, from the Sun
About 900 light-years. To cross it:
- Light900 years
- Voyager 1's speed16 million years
- Driving at 100 km/h9.71 billion years
Voyager 1 at the speed it moved outward over the year to 2026-10-25 (JPL Horizons). Driving: nonstop, never refuelling.
Facts
- It is about 200 million years old.
- At magnitude 3.3 it is an easy naked-eye target.
How it was found
- Ptolemy recorded it around 130 AD.
Where this comes from
- Dias et al. 2021, MNRAS 504, 356, Gaia DR2 (277 pc)
Every catalogue Ouranos draws is credited on the credits page.