Star cluster
Berkeley 23
Open star cluster · 933 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 | Gemini |
| Distance | 4,724 pc (15.4 thousand ly) |
| Age | 933 million years |
| Member stars (MWSC) | 63 |
| Reddening E(B−V) | 0.40 |
| Metallicity [Fe/H] | 0.07 |
| Source | MWSC (Kharchenko et al. 2013) |
| Right ascension (J2000) | 6h 33m 18.0s |
| Declination (J2000) | +20° 31′ 30″ |
In the sky
Visible from the whole Northern Hemisphere and south to latitude 69° S. North of latitude 69° N it never sets. It stands highest at midnight in December, the best time to observe it.
Through a telescope from Earth
Light's journey
The light you see tonight set out 15 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 273 million years.