Galaxy · Spiral
NGC 817
NGC 817 is a galaxy in the direction of the constellation Aries, 210.3 million light-years away.
| Type | Spiral |
|---|---|
| Constellation | Aries |
| Distance | 210.3 million light-years (64.49 Mpc) |
| Diameter | 72,500 light-years · 0.83 × the Milky Way |
| Absolute magnitude | magnitude −19.98 |
| Apparent magnitude | magnitude 14.07 |
| Luminosity | 0.43 × the Milky Way |
| Right ascension (J2000) | 2h 07m 33.7s |
| Declination (J2000) | +17° 12′ 09″ |
| Source | 2MASS Redshift Survey (Huchra et al. 2012) |
In the sky
A telescope is needed to see it: its apparent magnitude is 14.07. Visible from the whole Northern Hemisphere and south to latitude 73° S. North of latitude 73° N it never sets. It stands highest at midnight in October, the best time to observe it.
Through a telescope from Earth
Light's journey
The light you see tonight set out 210 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 3,731.3 billion years.