Star cluster
Ruprecht 100
Open star cluster · 398 million years
An open cluster of stars born together from the same gas cloud in the Milky Way’s disc; the Galaxy’s tidal forces will disperse it within a few hundred million years. Position, distance, age and member count come from the MWSC catalogue; the total brightness is roughly estimated from the member count.
| Type | Star cluster |
|---|---|
| Constellation | Crux |
| Distance | 2,589 pc (8.4 thousand ly) |
| Age | 398 million years |
| Member stars (MWSC) | 111 |
| Reddening E(B−V) | 0.73 |
| Source | MWSC (Kharchenko et al. 2013) |
| Right ascension (J2000) | 12h 05m 45.6s |
| Declination (J2000) | −62° 37′ 01″ |
In the sky
Visible from the whole Southern Hemisphere and north to latitude 27° N. South of latitude 27° S it never sets. It stands highest at midnight in March, the best time to observe it.
Through a telescope from Earth
Light's journey
The light you see tonight set out 8,444 years ago. At that time the first farming villages were being founded; there was no writing yet. At the speed of Voyager 1, the fastest craft leaving the Solar System (16.9 km per second), the trip would take 150 million years.