Galaxy · Spiral
NGC 7640
NGC 7640 is a galaxy in the direction of the constellation Andromeda, 25.8 million light-years away.
| Type | Spiral |
|---|---|
| Constellation | Andromeda |
| Distance | 25.8 million light-years (7.90 Mpc) |
| Diameter | 81,500 light-years · 0.93 × the Milky Way |
| Absolute magnitude | magnitude −19.80 |
| Apparent magnitude | magnitude 9.69 |
| Luminosity | 0.36 × the Milky Way |
| Right ascension (J2000) | 23h 22m 06.6s |
| Declination (J2000) | +40° 50′ 44″ |
| Source | Updated Nearby Galaxy Catalog (Karachentsev et al. 2013) |
In the sky
A telescope is needed to see it: its apparent magnitude is 9.69. Visible from the whole Northern Hemisphere and south to latitude 49° S. North of latitude 49° N 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 26 million years ago. At that time the dinosaurs were gone and mammals were diversifying; there was no human lineage yet. At the speed of Voyager 1, the fastest craft leaving the Solar System (16.9 km per second), the trip would take 457.1 billion years.