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)
The Porter Garden Telescope The Porter Garden Telescope The Porter Garden Telescope, was an innovative ornamental telescope for the garden designed by Russell W. Porter and commercialized by Jones & Lamson Machine Company at the beginning of the 1920´s in the United States. Oriented to users with high purchasing power, and constructed in statuary bronze, it could be left permanently outdoors like sculptures and sundials, keeping the delicate optics in a case. It was embellished with floral ornament, with a style close to the art nouveau. In its base were the names of celebrated astronomers: Galileo, Kepler, and Newton. The part called the bowl