POWERHOUSE COLLECTION

Telescope eyepieces used at Sydney Observatory

Object No. H10294

In 1874, after two years of enquires, the NSW Government Astronomer H. C. Russell acquired a number of new instruments in preparation for the upcoming Transit of Venus. One of these was a new 11.4 inch telescope (H9886) purchased for the observation of double stars from the optician and instrument maker, Hugo Schroeder. In 1870 Schroeder had made an objective for the Hamburg Observatory and the success of this instrument may have been one reason Russell sought him out. As well as the telescope Russell purchased some additional instruments from Schroeder for use with the telescope. These were a solar polarising eyepiece (H10380) designed for viewing the sun, a filar micrometer mounted on a graduated circuit (H10007) and these eyepieces. A sun diagonal (H10295) used in conjunction with the Schroeder telescope was purchased separately. These quality eyepieces made by Carl Zeiss of Jena, were used with the 11.4-inch telescope but it is uncertain as to whether they were purchased at the same time. The fact the Zeiss lenses are all contained in a wooden box with Scroeder's name plate on it implies this may have been the case. The quality of these eyepieces was commented on by Russell who felt that the definition of the telescope was superb especially when using the achromatic eyepieces supplied by Dr. Schroeder. References Haynes, Raymond, Haynes, Roslynn, Malin, David, McGee, Richard, Explorers of the Southern Sky, Cambridge University Press, 1996 Russell, H., C., "Report of Astronomer for 1874 & 1875', New South Wales Government Printer, 1876 Auerbach, F., The Zeiss Works and the Carl Zeiss Foundation in Jena, W. & G., Foyle, London, England, about 1925? Geoff Barker, August, 2007

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Summary

Object Statement

Refractor telescope eyepieces in a box (7), optical equipment, brass / glass / wood / fabric, used at Sydney Observatory, made by Carl Zeiss and Hugo Schroeder, Germany, 1874-1900

Physical Description

Optical equipment, seven refractor telescope eyepieces, brass / glass / wood / fabric, used at Sydney Observatory, made by Carl Zeiss and Hugo Schroeder, Germany, 1874-1900. Seven lenses for use with an 11 1/2-inch refractor telescope. Each of the lenses are enclosed inside a metal container and stored together in a wooden box with a hinged lid.

PRODUCTION

Notes

Carl Zeiss 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 (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. These eyepieces were used with the 11 1/2-inch refractor telescope, and were sold by Hugo Schroeder whose name is on the label in the wooden box. References Auerbach, F., The Zeiss Works and the Carl Zeiss Foundation in Jena, W. & G., Foyle, London, England, about 1925? By Geoff Barker, November, 2007

HISTORY

Notes

According to the blue file, the eyepieces were used with the 11 1/2" refractor telescope at the Sydney Observatory. Eyepieces come from the collection of the Sydney Observatory (according to the object file).

SOURCE

Credit Line

Ex Sydney Observatory, 1984

Acquisition Date

20 July 1984

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