Star cluster
ESO 520-20
Open star cluster · 1.4 billion 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 | Ophiuchus |
| Distance | 2,041 pc (6.7 thousand ly) |
| Age | 1.4 billion years |
| Member stars (MWSC) | 172 |
| Reddening E(B−V) | 2.33 |
| Source | MWSC (Kharchenko et al. 2013) |
| Right ascension (J2000) | 17h 43m 36.1s |
| Declination (J2000) | −24° 43′ 05″ |
In the sky
Visible from the whole Southern Hemisphere and north to latitude 65° N. South of latitude 65° S it never sets. It stands highest at midnight in June, the best time to observe it.
Through a telescope from Earth
Light's journey
The light you see tonight set out 6,657 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 118 million years.