Topic summary
Crossley Reflector
Extracted from the Wikipedia article Crossley telescope.
History
Observations by Keeler helped establish large reflecting telescopes with metal-coated glass mirrors as astronomically useful, as opposed to earlier cast speculum metal mirrors. Great refractors were still in vogue, but the Crossley reflector foreshadowed the success of large reflectors in the 1900s. Other large reflectors followed, such as the Harvard 60-inch Reflector (152 cm), also with a mirror by A.A. Common, or the 1 Meter Spiegelteleskop (39.4 inch reflector) of the Hamburg Observatory. At this time the 72-inch Leviathan of Parsonstown was the largest by aperture, but it used a metal mirror. Despite the accomplishments of reflectors under Herschel, in the 19th century much of the astronomical community used relatively small refractors, often just a few inches in aperture, save for a few larger ones.