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COLLECTION Identifier: UAV 630.10

Records of Harvard College Observatory Director Joseph Winlock


Joseph Winlock (1826-1875) was an astronomer and mathematician who served as the third director of the Harvard College Observatory from 1866 until his death on June 11, 1875. The records document Joseph Winlock's tenure as director, and primarily consist of Winlock's incoming and outgoing correspondence files. The letters relate to Observatory publications, relationships with other scientific institutions, and discussions of astronomical and meteorological information. The records also include a bound volume of drafts and memoranda related to Observatory funds, which provides some insight into the Observatory’s finances from 1866 to 1874.


  • Creation: 1862-1882


Conditions Governing Access

The Records of Harvard College Observatory Director Joseph Winlock are open for research with the exception of a few restrictions due to physical format, which are noted throughout the finding aid. Please consult with reference staff for details.


5.27 cubic feet (11 document boxes, 3 flat boxes, 2 legal half-document boxes, 1 extra-tall document box)

The Records of Harvard College Observatory Director Joseph Winlock document Winlock's tenure as director of the Harvard College Observatory from 1866 to 1875, and primarily consist of incoming and outgoing correspondence files. The letters, written both to and from Winlock and his assistant, Arthur Searle, relate to Observatory publications, primarily the Annals of the Harvard College Observatory, include discussions of astronomical and meteorological information, and document relationships with several other scientific institutions, government agencies, colleges and universities, individuals, and other Harvard departments. Scattered correspondence between Winlock and various Harvard departments, such as the Bursar's Office and the Steward's Office, shows how the Observatory fit into the larger university context and provides a glimpse into Harvard's operations. Letters from international organizations in Canada and several European nations demonstrate the prominent reputation and international respect that the Harvard College Observatory had developed by the time Winlock had become director. Many notable Bostonians were involved with the establishment and ongoing financial support of the Observatory, including J.I. Bowditch, Uriah Boyden, and Eliza Quincy, whose correspondence are included in the records. Letters from local agencies reveal how dependent the government was on the Observatory's scientific data, especially rainfall totals and temperature recordings. Correspondence between the United States Coast Survey and United States Naval Observatory highlights the importance and depth of the Observatory's collaboration with the federal government. The records also includes a bound volume of drafts and memoranda related to Observatory funds, which provides insight into the Observatory’s finances from 1866 to 1874. A limited number of items fall outside of the dates of Winlock's tenure; the provenance of these documents is unclear.

Biographical note on Joseph Winlock

Joseph Winlock (1826-1875), Director of the Harvard College Observatory, was a professor of astronomy and geodesy, and was responsible for making many important improvements to the Observatory. Winlock was born on February 6, 1826 in Shelby County, Kentucky. He graduated from Shelby College in Kentucky in 1845, then was appointed professor of mathematics and astronomy at the college, where he remained until 1852. Winlock also served as assistant professor in mathematics at the Naval Observatory in Washington, D.C., and was head of the mathematics department at the Naval Academy in Annapolis, Maryland. He was appointed the third director of the Harvard College Observatory in 1866, a post he maintained until his death on June 11, 1875. While at the Observatory, Winlock was responsible for obtaining many pieces of new scientific equipment, including a photometer, several spectroscopes, a mean time chronometer, and a Bond chronograph, among many others. He also invented several important instruments, including the Hygrophant, a mechanism that measured the percentage of moisture in the air, and introduced a system of communicating time for the cities of Boston and Cambridge, as well as other large towns in New England. He was particularly interested in conducting measurements with the meridian circle, creating a catalogue of double stars, and investigating stellar photometry. In 1869, Winlock led a solar eclipse expedition to Kentucky, where his astronomy career had begun, and in 1870, at the request of the United States Coast Survey, he traveled abroad to Spain, where he was able to photograph the corona for the first time. A lunar impact crater on the far side of the Moon is named after him, recognizing Winlock's contributions to the field of astronomy.

Biographical note on Arthur Searle

Arthur Searle (1837-1920), Phillips Professor of Astronomy, was responsible for observing many stars, double stars, comets, planets, and asteroids throughout his career. He was born was in London, England in October, 1837. Searle graduated from Harvard College in 1856, received his Master’s degree in 1859, then went on to engage in various professions, including the study of chemistry, school teaching, sheep farming in California, stock brokering, and working with the statistical department of the United States Sanitary Commission. He began working at the Harvard College Observatory in 1868, was named assistant in 1869; assistant professor in 1883; Phillips Professor of Astronomy in 1887; and Phillips Professor Emeritus in 1912. He also taught a class in astronomy at Radcliffe College for many years. Searle died in October, 1920 in Cambridge, Massachusetts.

Historical note on the Harvard College Observatory

The Harvard College Observatory was established in 1839 when, after decades of attempts to develop an observatory, the Harvard Corporation hired William Cranch Bond, a Boston clockmaker, as the Astronomical Observer to the University. His personal astronomical equipment was transferred to the Dana House (now the Dana-Palmer House), where the observatory was housed until 1843. Scholars and students at Harvard University had studied astronomy since the seventeenth century, but it wasn’t until a large comet sparked public interest in 1843 that donors began to give funds to the University build an observatory. A bequest from Edmund Bromfield Phillips in 1849 provided $100,000 toward the construction of a new observatory, and President Josiah Quincy secured $25,730 from ninety-four donors that year. That same year, Harvard ordered a fifteen-inch diameter lens from Merz and Mahler of Munich to build a Great Refractor telescope. The Great Refractor was used to determine stellar positions and the visual observation of planets, variable stars, comets, and nebulae. The first observation with the telescope was of the Moon on June 24, 1847, which was followed by several significant achievements. The eighth satellite of Saturn was discovered in 1848 by W.C. Bond and his son, George P. Bond. In 1850, Saturn's crape, or inner, ring was first observed, also by the Bonds. In 1844, the University moved the equipment to the main building at a site fifty feet higher in elevation than the city of Cambridge, now known as Observatory Hill.


The records are arranged in three series. The contents of each series have been arranged in chronological order by the archivist:

  1. Incoming correspondence, 1862-1882
  2. Outgoing correspondence, 1866-1875
  3. Memoranda relating to Observatory funds, 1866-1874

Related Materials

The Harvard University Archives also holds the Records regarding the appointment of a director for the Observatory, 1865 (UAI 20.865.2), as well as many other Observatory record series (UAV 630.xx).

Processing Information

This finding aid was created by Olivia Mandica-Hart in October 2018. Titles enclosed in brackets were devised by the archivist.

Harvard College Observatory. Records of Harvard College Observatory Director Joseph Winlock, 1862-1882 : an inventory
Harvard University Archives
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Language of description

Repository Details

Part of the Harvard University Archives Repository

Holding nearly four centuries of materials, the Harvard University Archives is the principal repository for the institutional records of Harvard University and the personal archives of Harvard faculty, as well as collections related to students, alumni, Harvard-affiliates and other associated topics. The collections document the intellectual, cultural, administrative and social life of Harvard and the influence of the University as it emerged across the globe.

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