Deep sky · Galaxy in Andromeda · M 31 · NGC 224
M 31
Andromeda Galaxy
The Andromeda Galaxy — a trillion suns, and the farthest thing most people will ever see with their own eyes.
- Type
- Galaxy
- Designations
- M 31 · NGC 224
- Constellation
- Andromeda
- Apparent magnitude
- 3.4
- Apparent size
- 3.2° × 62′
- Position (J2000)
- RA 0h 43m · Dec +41° 16′
History
The Persian astronomer al-Ṣūfī described it as a “little cloud” in 964. In 1923 Edwin Hubble found a Cepheid variable in it and showed it lies far outside the Milky Way — the moment the universe became full of galaxies.
Science
Andromeda and the Milky Way are falling towards each other at about 110 km/s. They may merge in four to five billion years, though the newest measurements make it closer to a coin toss.
Look for
The glow you see is only its bright core. In photographs it spans six times the width of the full Moon.