William Lassell (June 18, 1799 &ndashh; October 5, 1880) was a British astronomer.
He made his fortune as a beer brewer, which enabled him to indulge his interest in astronomy. He built an observatory near Liverpool with a 24-inch reflector telescope, for which he pioneered the use of an equatorial mount for easy tracking of objects as the earth rotates. He ground and polished the mirror himself, using equipment he constructed himself.
Later, in 1855, he built a 48-inch telescope, which he installed in Malta because of the better observing conditions (weather) compared to Britain.
In 1846 he discovered Triton, the largest moon of Neptune, soon after the discovery of Neptune itself.
In 1848 he independently co-discovered Hyperion, a moon of Saturn.
In 1851 he discovered two new moons of Uranus, which he named Ariel and Umbriel.
He served as president of the Royal Astronomical Society for two years starting in 1870
When Queen Victoria visited Liverpool in 1851, Lassell was the only local she specifically requested to meet.
Upon his death, he left a fortune of £80,000 (equivalent of multi-millionaire by today's standards).