Smithsonian Institution
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Asset Name:
media:NASM-A19930093002_DSH01

File Usage:

Not determined
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Object details:

Object Name: Drive Motor, Mirror Grinding Machine, G. W. Ritchey
Smithsonian Record ID: edanmdm:nasm_A19930093002

	Object Name
	Drive Motor, Mirror Grinding Machine, G. W. Ritchey

	Metadata Usage
	Not determined

	Guid
	http://n2t.net/ark:/65665/nv95ebd4673-aa37-4d5d-afb3-1748ef80fd2f

	Data Source
	National Air and Space Museum

	Manufacturer
	Dynamatic and Cleveland Gear

	Materials
	Overall - iron, aluminum

	Dimensions
	3-D: 61 x 121.9 x 61cm (24 x 48 x 24 in.)

	Summary
	This is the electric motor that replaced the original overhead belt-driven drive on the mirror-grinding machine built by George Willis Ritchey at the Yerkes Observatory in Williams Bay, Wisconsin, in the late 1890s. The object is a commercial product, a Dynamatic "Ajusto-Speed" 5 hp 1750 rpm electric motor, model MO 100005-0904, serial 72450-4, with Cleveland right-angle drive. The original grinding machine was used under the sponsorship of Hale to grind a 60-inch mirror initially intended for the Yerkes Observatory. The grinding machine was moved to Pasadena in 1904 to complete work on the mirror; at some point it 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 is not known when the replacement motor was installed, but it was likely when the machine was transferred to the Caltech campus. It was donated to NASM by the Lick Observatory in 1993 and shipped in March of that year.

	Alternate Name
	Ritchey Mirror Grinding Machine Motor

	Country of Origin
	United States of America

	Credit Line
	Gift of the Lick Observatory, University of California.

	Inventory Number
	A19930093002

	Type
	EQUIPMENT-Power Sources

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