Charles Messier spent his life obsessed with hunting comets, and history remembers him for the catalog of fuzzy objects he compiled so he could ignore them. This episode explores the 18th-century French astronomer's story, from a childhood in Lorraine marked by the death of six siblings and his father, to the Great Comet of 1744 and the 1748 annular eclipse that offered a grieving boy the reliable order of the sky.

We follow his 1751 arrival in Paris to work under Navy astronomer Joseph-Nicolas Delisle, the longitude problem that made the sky a giant clock, his 1753 transit of Mercury observation, and the grueling work of comet hunting through Parisian smoke with a four-inch refractor. Messier discovered 13 comets, earned the nickname ferret of comets from King Louis XV, and joined the Royal Society and the French Academy of Sciences. With  ...