Many of the best known astronomers who helped pioneer astronomy could not have succeeded without the financial resources to do so. William Hershchel married the widow of a wealthy brewer; Percival Lowell was a dignitary and member of an affluent family. William Lassell (1799-1880) was rich, too – also with the help of beer. At 26 he founded his own brewery and eventually made a fortune in England. This allowed him to devote full time to his interest in astronomy. In doing so, he, with others, laid the foundations for the development of modern telescopes.
Lassell made his first telescope when he was 21, a 7-inch Newtonian. A brewer by profession, he possessed an unusual talent in mechanical ability, and spent much of his time building telescopes. Like William Herschel, he was a workaholic. When his business prospered Lassell designed and built a 24 inch reflector, using insights provided by another telescope builder, Lord Rosse of Ireland. After a visit to Rosse’s
Workshop, Lassell began construction using an improved grinding process of his own invention. He had problems producing a 24-inch speculum (the primary reflecting mirror) which produced an adequately sharp image. Unsatisfied with the mirror’s quality, he sought the help of a friend, James Nasmyth.
Naysmith, a skillful Scottish engineer, operated a manufacturing company that built steam engines, machinery, and tools. Many of these were Nasmyth’s own designs. He too, had accumulated a fortune to fuel his hobby, astronomy. At 48, Nasmyth retired devoting full time building telescopes and observing. An expert in casting metals, he developed an alloy of 15 parts pure tin, 32 parts pure copper and 1 part arsenic. His technique in casting this alloy produced a brilliant speculum that resulted in the Lassell comment, “…it made my mouth water!”
Lassell finished his 24 inch telescope in 1846. It was one of the finest of the time. With it he discovered Triton, the brightest moon of Neptune; Hyperion, a moon of Saturn; and two moons of Uranus, Ariel and Umbriel in 1851. In 1852 he moved his telescope from England to Malta (in the Mediterranean just south of Sicily) for the winter. Because the move was such a success he decided to build an even bigger and better 48-inch telescope in England, undertaking this venture in 1859. Lassell loved to look at nebulae. He recognized the spiral form in galaxies and, with the help of assistants and other astronomers, catalogued 600 previously unknown nebulae.
William Herschel, in the previous century, tried to make a larger telescope but ended up with an unwieldy monster. Lassell’s finished product was an f/9.4 Newtonian, and unlike the larger telescopes of Herschel was versatile and effective. The tube length was 37 feet, and the tube itself was constructed of flat iron bars. A revolving observing tower rode about the telescope on rails adjusted to the telescope’s position, and had provisions for charts, eyepieces, books, and other small instruments. But its main function was to protect the observer from wind and dew. The telescope was driven with a manual hand crank. An attendant would turn the crank in synchronous time with a clock. The entire structure weight about eight tons. In 1861 Lassell moved his 48-inch to Malta. He returned to England in 1865. The telescope continued to be used until just before his death in 1880 when it finally outlived its usefulness and was sold for scrap metal.
“When witnessing the breakup of the specula” , Lassell wrote, “I was not without a pang or two on hearing the heavy blows of sledgehammers necessary to overcome the firmness of the alloy.
(First published in the Johnson Space Center Astronomical Society newsletter Starscan 1987 by Jan W. Railsback; modified for 2010).
Sources and recommended reading:
The Astronomical Scrapbook, by Joseph Ashbrook
The History of Astronomy from Herschel to Hertzsprung, by Dieter B. Herrman