William Lassell (Bolton, 1799 / Maidenhead, 1880) was a British brewer who excelled as an amateur astronomer. He became fond of astronomy by reading the works of William Herschel. He learned in a self-taught way to build telescopes and, aware of the discovery of the planets Neptune, 17 days after its discovery, he directed his telescope to the planet, discovering its satellite Triton on the night of October 10, 1846. He also discovered Hyperion, satellite of Saturn on September 18, 1848, and the satellites of Uranus, Ariel and Umbriel (October 24, 1851). In 1852 he moved to Malta in search of clearer skies and in 1859 he commissioned the construction of a new 122 cm aperture telescope, completed in 1861. From there he studied planet, satellites and comets, as well as the Mercury transit of 1868.
