There are four that I can think of:
- 1. The Milky Way. This is our galaxy. We're in it, so we can see it in all directions. You can see the largest concentration of stars in a band stretching across the sky. It is quite diffuse, so you need to be somewhere really dark to see it well. The centre is in the constellation of Sagittarius.
- 2-3. The Magellanic Clouds (Large and Small) are two small(ish) galaxies which are being accreted by the Milky Way. You can only see them from the southern hemisphere.
- 4. The Andromeda Galaxy (or M31) can be seen as a fuzzy patch in the constellation of Andromeda (again only if it is very dark out).
Galaxies are diffuse patches of light, so they are hard to see unless the sky is very dark. You can't even see the Milky Way from most cities, and Andromeda is even harder. It is possible though.
This page was last updated on March 31, 2016.