Kellner, Carl, born March 26th 1826 in Hirzenhain, Germany, died May 13th 1855 in Wetzlar. His father was Albrecht (1791-1865), who lead the Buderus foundry in H. His mother was Elisabeth Rudersdorf (1751-1848), daughter of a shoemaker in Haiger. After school in 1843 he went to Giessen for an apprenticeship with the mechanic Carl Ludwig Sartorius, in 1845 to Hamburg to work at Repsold & Sons where he stayed for 18 months. There he met Moritz Hensold, with whom he opened an workshop for mechanical and optical parts in Wetzlar 1848. The opening of the workshop was offically announced with the publishing of his paper "Das orthoskopische Ocular" in 1849. This publication on important improvements on eyepieces for telescopes and microscopes made him well known in the optical and scientific field. The improvements included a wider field of view and correcting for abberations. Based on this paper he received many orders for optical elements. His customers list included Argelander, Liebig and others. The eyepieces he made were for use mainly in telescopes, but soon also found their way into microscopes. Fimally Kellner and his twelve employees build complete instruments. Until his early death in 1855 his workshop manufactured at least 130 microscopes, 5 big telescopes and a number of small handheld telescopes. The consequences of Kellners work are threefold. First, he founded the optical industry at Wetzlar, turning this town in to a prospering place. Soon after Kellners death Ernst Leitz took over the workshop. Leitz is a still busy optical company today. Second, he together with the Zeiss shop in Jena made Germany independent from the import of optical components from France and England. And third his microscopes and subsequent instruments from Wetzlar allowed progress in medical work.
References: 1. RÖSCH, S., in: Neue Deutsche Biografie, Vol. 11, p. 475-76