Star cluster
Pleiades (M45)
The Seven Sisters — the most famous open cluster
A 100-million-year-old open cluster in Taurus; it holds ~1,000 stars, and its bright B-type members light up the dust cloud they are passing through as a blue reflection nebula. Every culture in human history has a name for it.
| Type | Star cluster |
|---|---|
| Constellation | Taurus |
| Distance | 136 pc (444 light-years) |
| Apparent magnitude | 1,6 |
| Age | ~100 million years |
| Number of stars | ~1 000 |
| Core radius | ~2.5 pc |
| Right ascension (J2000) | 3h 46m 60.0s |
| Declination (J2000) | +24° 07′ 01″ |
In the sky
Visible from the whole Northern Hemisphere and south to latitude 66° S. North of latitude 66° N it never sets. It stands highest at midnight in November, the best time to observe it.
Through a telescope from Earth
Light's journey
The light you see tonight set out around the year 1582. At the speed of Voyager 1, the fastest craft leaving the Solar System (16.9 km per second), the trip would take 7.9 million years.