"Photographing Andromeda was a herculean task because the galaxy is a much bigger target on the sky than the galaxies Hubble routinely observes, which are often billions of light-

Messier 31 is located 2.5 million light-years away from Earth and was a much bigger target in the sky than the galaxies Hubble routinely observes.

Andromeda is the closest large galaxy to the Milky Way. And it is getting closer, as the two will merge in several billion years. It has been an object of study for centuries, but we have never seen it like this.