Telescope eyepiece, 'Kellner', metal / glass, made by Carl Zeiss, Jena, Germany, 1890-1920, used at Sydney Observatory, New South Wales, Australia, 1890-1920
Eyepieces, for use with telescopes, vary widely in size, focal length, and design. This eyepiece was used at Sydney Observatory in the late 1800s and early 1900s.
Carl Kellner designed the first modern achromatic eyepiece in 1850. His development of this eyepiece provided better colour correction and edge sharpness than previous designs.
Carl Zeiss was one of the 19th century's most significant makers of optical instruments, including eyepieces such as this one. This eyepiece remains of national significance due to its pioneering role in Australian science and its association with Australia's earliest astronomers.
Written by Erika Dicker
Assistant Curator, 2007.
The eyepiece was made by Carl Zeiss in Jena Germany between 1890 and 1920.
In 1846 Carl Zeiss (1816-1888) started his instrument making business in a small town of Jena in Germany. He quickly became interested in optics and by 1848 was making and designing microscopes. By 1866 Zeiss realised that to expand his business he needed someone with a greater understanding of optics. Zeiss found the right person in Ernst Abbe (1840-1905) and by 1870 they had devised a new way for computing the manufacture of optical lenses which would improve performance by eradicating much of the colour and spherical distortion of the lens.
In 1879 they produced the homogenous immersion objective but the flint and crown glass which they used to make their lenses needed to be improved before they could perfect their lenses. Optical glass made from silica, soda and potash was supplied by manufacturers who used the same recipes for much of the nineteenth century. It was only after Zeiss and Abbe teamed up with the glass maker Otto Schott in 1881 that they were able to produce a better quality glass without so much of the characteristic green or yellow tinges.
In 1886 Zeiss and Abbe produced the apochromatic (better colour correction than an achromatic) microscope lens. Consisting of ten lenses it effectively removed secondary spectra distortion and spherical aberration. Using the new glass and Abbe's formulas the Zeiss factory began producing their famed anastigmatic photography lenses in 1890. It was around this time that the Zeiss works began constructing eye pieces and objectives for telescopes.
Auerbach, F., The Zeiss Works and the Carl Zeiss Foundation in Jena, W. & G., Foyle, London, England, about 1925?
Written by Geoff Barker,
Assistant Curator, November 2007.
This eyepiece was used at Sydney Observatory, Sydney, New South Wales, Australian, between 1890 and 1920.