24 October

1851: On 24 October 1851, British astronomer William Lassell discovered Ariel and Umbriel, satellites of Uranus.

Like most of the other Uranian moons Ariel is named after a Shakespearean character. The name Umbriel comes from Alexander Pope's The Rape of the Lock.

Lassell had previously also discovered Neptune's largest satellite, Triton and (with American astronomer George Bond) discovered Saturn's moon Hyperion.

1601: On 24 October 1601, Tycho Brahe died.

Brahe was a Danish astronomer whose work in developing astronomical instruments and in measuring and fixing the positions of stars paved the way for future discoveries.

His observations, the most accurate possible before the invention of the telescope, included a comprehensive study of the Solar System.