George Willis Ritchey built this mirror grinding machine at the Yerkes Observatory in Williams Bay, Wisconsin, in the late 1890s. Under the sponsorship of George Ellery Hale, the machine was used to grind a series of telescope mirrors starting with a 60-inch mirror for a telescope initially intended for the Yerkes Observatory. The grinding machine was moved to Pasadena in 1904 to complete work on the 60-inch mirror. At some later time the apparatus was transferred to the California Institute of Technology. The Institute then sold the machine to the Lick Observatory of the University of California in 1949. The machine was used for making numerous mirrors over the next four decades and extensively modified over that period. It embodies the "sub-diameter tool" design approach to making large telescope mirrors whereby the grinding tool is drawn across the mirror blank by programmable rotating arms. It was donated to NASM by the Lick Observatory in 1993 and shipped in March of that year.
Display Status
This object is on display in Space Science at the Steven F. Udvar-Hazy Center in Chantilly, VA.
Object Details
Country of Origin
United States of America
Type
INSTRUMENTS-Scientific
Designer
George Willis Ritchey
Manufacturer
Yerkes Observatory
Dimensions
3-D: 274.3 x 365.8 x 243.8cm (108 in. x 12 ft. x 96 in.)
Materials
Wood and iron construction, leather belts, steel hardware
Alternate Name
Ritchey Mirror Grinding Machine
Inventory Number
A19930093000
Credit Line
Gift of the Lick Observatory, University of California
Data Source
National Air and Space Museum
Restrictions & Rights
Usage conditions apply
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