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)
James Lick telescope James Lick telescope The James Lick Telescope is a refracting telescope built in 1888. It has a lens in diameter- a major achievement in its day. The instrument remains in operation and public viewing is allowed on a limited basis. Also called the "Great Lick Refractor" or simply "Lick Refractor", it was the largest refracting telescope in the world until 1897 and now ranks third, after the 40-inch unit at the Yerkes Observatory and the Swedish 1-m Solar Telescope. The telescope is located at the University of California's Lick Observatory atop Mount Hamilton at an elevation of above sea level.