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)
Largest shipwrecks on the Great Lakes Isaac M. Scott !scope="row"|"SS Charles S. Price Largest shipwrecks on the Great Lakes The Great Lakes are the largest bodies of freshwater in the world. They are five giant freshwater lakes, named Lake Superior, Lake Huron, Lake Michigan, Lake Erie and Lake Ontario. Thousands of vessels have sailed on the lakes from the late 15th century to the present day. Thousands of ships sank on the lakes from 1679 when "LaSalle"'s wooden barque the "Le Griffon" was lost, to the 1975 sinking of the giant freighter "Edmund Fitzgerald" on Lake Superior. Many of these shipwrecks were never found, so the