Collection Guide
Collection Title:
Collection Number:
Get Items:
Mount Wilson Observatory Optical Shop Papers
mssMtWilson2
View entire collection guide
Search this collection
Table of contents
Contributing Institution:
The Huntington Library
Title: Mount Wilson Observatory Optical Shop Papers
Identifier/Call Number: mssMtWilson2
Physical Description:
4.51 Linear Feet
(9 boxes)
Date (inclusive): 1911-1966
Date (bulk): 1930-1947
Abstract: This collection contains records of the Mount Wilson Observatory Optical Shop, relating to the operation of the department
from 1911 to 1963 (bulk 1930-1947). The department was responsible for repairing and maintaining the Observatory's telescopes,
as well as for observatories around the United States. The materials include research and procedural notes, correspondence,
inventories and requisition slips, and job lists and employee time sheets.
Language of Material: English.
Open for use by qualified researchers and by appointment. Please contact Reader Services at the Huntington Library for more
information.
The Huntington Library does not require that researchers request permission to quote from or publish images of this material,
nor does it charge fees for such activities. The responsibility for identifying the copyright holder, if there is one, and
obtaining necessary permissions rests with the researcher.
[Identification of item]. Mount Wilson Observatory Optical Shop Papers, The Huntington Library, San Marino, California.
Immediate Source of Acquisition
Deposit, Observatories of the Carnegie Institution of Washington Collection, 1988. Approximately fifty additional separate
collections form the Mount Wilson Papers of the Observatories of the Carnegie Institution of Washington and are available
for research in the Manuscripts Department of the Huntington Library.
Founded in December 1904 by George Ellery Hale and funded by the Carnegie Institution, the Mount Wilson Observatory quickly
became one of the 20th century's major astronomical research centers. Located just north of Los Angeles high atop the San
Gabriel Mountains, the observatory took full advantage of Southern California's clear nights and uniquely steady air. The
observatory's 60'' telescope completed in 1908 was the largest then in existence. In 1917, another Mount Wilson telescope,
100'' in diameter, claimed that title. The Optical Shop was the department responsible for repairing and maintaining these
telescopes. Optical Shop workers ground and polished mirrors, lenses, and prisms: tasks requiring meticulous precision and
technique. In addition to serving Mount Wilson, the Optical Shop produced optical instruments for observatories across the
country.
During the Second World War, the Mount Wilson Observatory Optical Shop played an important role in U.S. war effort. Shop
technicians produced roof prisms for military optics on a large scale, eventually publishing an instruction manual for other
optical workshops. Experiments with newly-invented Schmidt cameras helped develop the field of aerial photography. New camera
shutters and film sweep mechanisms were invented. Procedures for measuring lens resolution were tested.
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.
Arranged in 9 boxes in the following order:
- Boxes 1-2: Research and Procedure Notes
- Box 3: Correspondence
- Boxes 4-6; 9: Shop Inventories, Invoices, and Requisition Slips
- Boxes 7-8: Job Lists and Time Charts and Ephemera
Adams, Walter S. (Walter Sydney), 1876-1956.
- Addressee of Frank E. (Frank Elmore) Ross, 1874-1960 letter (1936, May 30). Box 3 (1).
- Addressee of B.H. Witherspoon letters (1941, July-1941, Aug.). Box 3 (5). Addressee of Benjamin Liebowitz letter (1945, Dec. 10). Box 3 (29).
Bowen, Ira Sprague, 1898-1973.
- Addressee of Jet Propulsion Laboratory (U.S.) letter (1949, Nov. 22). Box 3 (40).
Subjects and Indexing Terms
Astronomers -- United States -- Correspondence
Astronomical observatories -- California -- Wilson, Mount (Mountain)
Astronomical photography -- Equipment and supplies.
Astronomy -- United States -- History -- 20th century -- Sources
Astrophysics -- History -- 20th century -- Sources
Telescopes -- Design and construction -- History -- Sources
Inventories -- California -- 20th century
Letters (correspondence) -- United States -- 20th century
Notebooks -- California -- 20th century
Time sheets -- California -- 20th century
Carnegie Institution of Washington.
Mount Wilson and Palomar Observatories.
Adams, Walter S. (Walter Sydney), 1876-1956