Mount Wilson Observatory Optical Shop Papers

The Mount Wilson Observatory Optical Shop Papers comprise 8 boxes of material relating to the operation of the department from 1911 to 1963 (bulk 1930-1947). This material is divided into four general categories: research and procedural notes, correspondence, inventories and requisition slips, and job lists and employee time sheets. Each group is arranged chronologically. Various scientific manuals, brochures, and unidentified notes have been gathered into a folder of ephemera.

Shop notebooks form the bulk of the research material. These notebooks outline various procedures for grinding and polishing mirrors, drilling glass, and configuring lenses. Several notebooks track the construction of the observatory's 100'' Hooker telescope as well as the 200'' Hale telescope housed at the California Institute of Technology's Palomar Observatory. Declassified research on aerial photography for the National Defense Research Committee is included in several progress reports.

The majority of correspondence is between Optical Shop technicians and astronomers both at Mount Wilson and elsewhere around the country. These letters are generally technical in nature with the various interlocutors trying to solve specific optical problems. Several manufacturing firms solicit the Optical Shop personnel about their products. Walter S. Adams and Don O. Hendrix participate in the bulk of the correspondence. Included is Hendrix's signed "Pledge of Secrecy" and commission from the Office of Scientific Research and Development. Inventory notebooks detail the supplies used in the Optical Shop: everything from towels and paper goods to slabs of optical glass and chemical solvents. Lists of lenses, mirrors, and prisms record material in stock and material lent out to other institutions. Requisition slips and shipping invoices illustrate the broad network of suppliers the shop needed for their highly specialized work.

A number of notebooks chart the myriad jobs the Optical Shop performed for both the Mount Wilson Observatory and other institutions. These notebooks assign each job a number, outline the work, and list the employees working on it. Separate employee time charts are also included with address and contact information for each.

Notable participants include: Walter S. Adams, who succeeded Hale as director of the observatory, Don O. Hendrix, the Shop's chief optician and Ira Sprague Bowen, Bannevar Bush, Robert E. Hopkins, Brian O'Brien, Frank E. Ross, and Jet Propulsion Laboratory.

Note: Two inventory notebooks have been treated for mold and are held separate from the main collection. Please contact Reader Services for access to these notebooks.