Carl August von Steinheil
Videos
Carl August von Steinheil was an Alsatian physicist, inventor, engineer and astronomer.
Reading telescopes by C.A. Steinheil purchased in 1865 on display in the Teylers Instrument Room
Speculum metal
Videos
Speculum metal is a mixture of around two-thirds copper and one-third tin, making a white brittle alloy that can be polished to make a highly reflective surface. It was used historically to make diffe
The speculum metal mirror from William Herschel's 1.2-meter (49.5-inch) diameter "40-foot telescope" at the Science Museum in London
Modern replica of Herschel's 6.2"-aperture Newtonian telescope which had a speculum metal main mirror
Leviathan telescope. Telescopes with speculum metal mirrors were a large breakthrough in aperture, but their drawbacks fueled competition from refractors
The metal mirror of the Leviathan, the largest telescope mirror until the 100-inch Hooker telescope of 1917 (a metal-on-glass mirror)