The Andromeda Galaxy, M31, the closest large galaxy to us, is a favorite target for amateur astronomers. I show how to take a good photograph of it. This galaxy has also been of great interest to professional astronomers. Indeed Edwin Hubble measured the brightnesses of Cepheid variables and showed that this galaxy is outside our own Galaxy. I show that a determined amateur photographer can photograph and identify the Cepheid variable stars used by Hubble to measure the distance to M31.