Star cluster
Riddle 15
Open star cluster · 1.0 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 | Aquila |
| Distance | 4,496 pc (14.7 thousand ly) |
| Age | 1.0 billion years |
| Member stars (MWSC) | 36 |
| Reddening E(B−V) | 1.67 |
| Source | MWSC (Kharchenko et al. 2013) |
| Right ascension (J2000) | 19h 11m 08.9s |
| Declination (J2000) | +14° 49′ 59″ |
In the sky
Visible from the whole Northern Hemisphere and south to latitude 75° S. North of latitude 75° N it never sets. It stands highest at midnight in July, 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 260 million years.