History of the telescope a wider field of view than a classic Cassegrain. During the period 1850–1900, reflectors suffered from problems with speculum metal mirrors, and a considerable number of "Great Refractors" were built from 60 cm to 1 metre aperture, culminating in the Yerkes Observatory refractor in 1897; however, starting from the early 1900s a series of ever-larger reflectors with glass mirrors were built, including the Mount Wilson 60-inch (1.5 metre), the 100-inch (2.5 metre) Hooker Telescope (1917) and the 200-inch (5 metre) Hale telescope (1948); essentially all major research telescopes since 1900 have been reflectors. A number of 4-metre class (160 inch)
40-foot telescope of the funding deal with the telescope, Caroline Herschel was granted a pension of £50 per year to be William's assistant. As a result, she was the first woman in England to be paid to carry out astronomy. The telescope was a local tourist attraction, visited by rich and famous people on their way to the nearby Windsor Castle to visit the King, and was featured on Ordnance Survey maps. It was the largest telescope in the world for 50 years. It was called the "40-foot telescope" as at the time telescopes were referred to by the length of their