Deep-Sky Object

Andromeda Galaxy (M31)

Also known as M31 · NGC 224 · NGC224 · ANDROMEDA · MESSIER 31 · ANDROMEDA NEBULA

The farthest thing you can see with the naked eye.

Visible tonight?

Below horizon · rises 13:18

Show on Sky Map

Rises: 13:18
Transit: 22:00
Sets: 06:41

Spiral galaxy 2.5 million light-years away. On a collision course with the Milky Way in ~4.5 billion years.

Finding it

From Cassiopeia's W, drop down to Mirach in Andromeda, then up two stars — a faint smudge.

Observing

Visible to the naked eye under dark skies. Binoculars show the bright core; a telescope reveals dust lanes.

Best viewing

Autumn evenings

Observing from Chitral

At Chitral's latitude Andromeda passes almost overhead in autumn, which is as good as it gets anywhere on Earth. From a Bortle 2–3 site it is an obvious elongated smudge to the naked eye once your eyes are 20 minutes dark-adapted. Use the widest field you own: at 2 million light-years it still spans six full-Moon widths, and a telescope shows less of it than binoculars do.

History & culture

Al-Sufi described it as a 'little cloud' in his Book of Fixed Stars in 964 CE — the earliest surviving record of any galaxy. It stayed a 'nebula' until Hubble found Cepheid variables in it in 1925 and pushed the universe wide open.