Galaxy · Spiral
NGC 7821
NGC 7821 is a galaxy in the direction of the constellation Cetus, 345.4 million light-years away.
| Type | Spiral |
|---|---|
| Constellation | Cetus |
| Distance | 345.4 million light-years (105.89 Mpc) |
| Diameter | 166,300 light-years · 1.9 × the Milky Way |
| Absolute magnitude | magnitude −22.09 |
| Apparent magnitude | magnitude 13.03 |
| Luminosity | 3 × the Milky Way |
| Right ascension (J2000) | 0h 05m 16.7s |
| Declination (J2000) | −16° 28′ 37″ |
| Source | 2MASS Redshift Survey (Huchra et al. 2012) |
In the sky
A telescope is needed to see it: its apparent magnitude is 13.03. Visible from the whole Southern Hemisphere and north to latitude 74° N. South of latitude 74° S it never sets. It stands highest at midnight in September, the best time to observe it.
Through a telescope from Earth
Light's journey
The light you see tonight set out 345 million years ago. At that time complex animals were spreading through the seas and over the land; there were no dinosaurs yet. At the speed of Voyager 1, the fastest craft leaving the Solar System (16.9 km per second), the trip would take 6,126.6 billion years.