Globular cluster
M 30 (NGC 7099)
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 0.5 % of the Sun’s. Distance, brightness and structure come from the Harris catalogue.
| Type | Globular cluster |
|---|---|
| Constellation | Capricornus |
| Distance | 8,100 pc (26.4 thousand ly) |
| Metallicity [Fe/H] | -2.27 |
| Half-light radius | 2.4 pc |
| Central concentration (c) | 2.50 · core-collapsed |
| Radial velocity | -184.2 km/s |
| Source | Harris 1996 (2010) |
| Right ascension (J2000) | 21h 40m 22.1s |
| Declination (J2000) | −23° 10′ 48″ |
In the sky
Visible from the whole Southern Hemisphere and north to latitude 67° N. South of latitude 67° S it never sets. It stands highest at midnight in August, the best time to observe it.
Through a telescope from Earth
Light's journey
The light you see tonight set out 26 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 469 million years.