About William Lassell
William Lassell was an English merchant and astronomer. He is remembered for his improvements to the reflecting telescope and his ensuing discoveries of four planetary satellites. In 1846, Lassell discovered Triton, the largest moon of Neptune, just 17 days after the discovery of Neptune itself by German astronomer Johann Gottfried Galle, using his self-built instrument. Lassell was a Fellow of the Royal Astronomical Society (FRAS) from 1839, won the Gold Medal of the Royal Astronomical Society in 1849, and served as its president for two years starting in 1870. There he had a 24-inch (610 mm) aperture metal mirror reflector telescope (aka the "two-foot" telescope), for which he pioneered the use of an equatorial mount for easy tracking of objects as the Earth rotates. In 1848, he independently co-discovered Hyperion, a moon of Saturn.
Biography source: Wikipedia. The profile adds birthday-specific historical context from the Celebs Birthday Today editorial database.