Globular cluster
M 12 (NGC 6218)
Globular cluster
A globular cluster of hundreds of thousands of old stars orbiting in the Galaxy’s halo: among the oldest objects of the Milky Way, about 12 billion years old. Its metal abundance is 4.3 % of the Sun’s. Distance, brightness and structure come from the Harris catalogue.
| Type | Globular cluster |
|---|---|
| Constellation | Ophiuchus |
| Distance | 4,800 pc (15.7 thousand ly) |
| Metallicity [Fe/H] | -1.37 |
| Half-light radius | 2.5 pc |
| Central concentration (c) | 1.34 |
| Radial velocity | -41.4 km/s |
| Source | Harris 1996 (2010) |
| Right ascension (J2000) | 16h 47m 14.2s |
| Declination (J2000) | −1° 56′ 55″ |
In the sky
Visible from the whole Southern Hemisphere and north to latitude 88° N. It stands highest at midnight in May, the best time to observe it.
Through a telescope from Earth
Light's journey
The light you see tonight set out 16 thousand years ago. At that time Homo sapiens was spreading out of Africa; there was no farming yet. At the speed of Voyager 1, the fastest craft leaving the Solar System (16.9 km per second), the trip would take 278 million years.