15 December

1612: On 15 December 1612, Simon Marius became the first person to spot another galaxy (Andromeda) through a telescope.

Marius was a German astronomer who made observations of the stars and planets using a telescope and published yearly astronomical tables.

Throughout most of his life, Marius copied data from other scientists and although he named the four moons of Jupiter, their discovery is generally credited to Galileo.

He described his first observation of Andromeda in the preface to his publication Mundus Jovialis as "like the flame of a candle seen through horn."