Galaxy · Irregular
NGC 3991S
NGC 3991S is a galaxy in the direction of the constellation Ursa Major, 146.7 million light-years away.
| Type | Irregular |
|---|---|
| Constellation | Ursa Major |
| Distance | 146.7 million light-years (44.97 Mpc) |
| Diameter | 101,600 light-years · 1.2 × the Milky Way |
| Absolute magnitude | magnitude −20.10 |
| Apparent magnitude | magnitude 13.16 |
| Luminosity | 0.48 × the Milky Way |
| Right ascension (J2000) | 11h 57m 30.5s |
| Declination (J2000) | +32° 20′ 03″ |
| Source | 2MASS Redshift Survey (Huchra et al. 2012) |
In the sky
A telescope is needed to see it: its apparent magnitude is 13.16. Visible from the whole Northern Hemisphere and south to latitude 58° S. North of latitude 58° N 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 147 million years ago. At that time dinosaurs ruled the Earth. At the speed of Voyager 1, the fastest craft leaving the Solar System (16.9 km per second), the trip would take 2,601.9 billion years.