Records of the Harvard College Observatory Time Service

In 1872, under Director Joseph Winlock, the Harvard College Observatory established the world’s first public time service, which it provided as a commercial service until 1892. Time standardization had became a priority throughout New England after a deadly train collision outside of Pawtucket, Rhode Island in 1853; this tragedy led to the expansion of the time service. Beginning in 1856, the Observatory began its time comparison practices; by 1872, the Observatory was selling its time service to railroads and businesses by sending hourly signals over Boston’s fire alarm system and distributing time across the region via Western Union telegraph lines. A highly precise clock maintained at the Observatory was recalibrated by stellar observation each clear night; the Observatory would then telegraph the correct time to Boston every day at noon, which was shared with ships via the Time Ball, located on the roof of the Equitable Life building on Milk Street. Shipboard navigators in Boston Harbor would then synchronize their marine chronometers. The Time Service turned into a lucrative money-making endeavor for the Observatory, earning approximately $2,400 a year through the 1870s and $3,000 in 1892, when time distribution was taken over by the United States Naval Observatory. The Observatory’s work resulted in the establishment of America’s first time zone. According to Professor Pickering, "one of the greatest advantages of the time-service to the observatory has been that it kept before the public the practical value of astronomical work."

In 1839, the Harvard Corporation appointed William Cranch Bond the first Astronomical Observer to the University, thereby taking the first step in establishing the Harvard College Observatory, after which the first telescope was installed in 1847. Scholars and students had studied astronomy at Harvard since the seventeenth century, but it wasn’t until a large comet sparked public interest in 1843 that donors began donating funds to build an observatory. During the tenure of the Harvard College Observatory’s first three directors, William Cranch Bond (1839-1859), George Phillips Bond (1859-1865), and Joseph Winlock (1866-1875), much of the Observatory’s research focused on lunar photography and chronometric activities to establish American longitude and to operate a time service for the United States government and commercial interests. In the late nineteenth century and early twentieth century, under the direction of Edward C. Pickering (1877-1919), research shifted from celestial mechanics and positional astronomy to astrophysics. The Observatory developed into a major research institution, focusing on photographic star surveys, spectroscopic analysis, and culminating in publication of the Henry Draper Catalogue, with spectroscopic classifications for 225,300 stars. During Pickering’s tenure, many women astronomers, including Annie Jump Cannon, Henrietta Swan Leavitt, Cecilia Payne-Gaposchkin, and Williamina Fleming performed essential research at the Observatory.

During the next several years, the Observatory became an important center for astronomical training and research, and building relationships with other institutions. Harlow Shapley, director from 1921 to 1952, inaugurated a program of graduate study in astronomy. Mandating that public education be a part of the Observatory’s mission, Shapley required students in the Harvard program to present lectures on astronomy to public school children. Donald H. Menzel (1952-1966) arranged a cooperative relationship with the Smithsonian Astrophysical Observatory (founded in 1890) and its relocation to Cambridge in 1955. Financial support for the Observatory expanded under Leo Goldberg (1966-1970), and in 1973 George B. Field (1972-1983) created an administrative umbrella organization, the Harvard-Smithsonian Center for Astrophysics, to coordinate the Smithsonian Astrophysical Observatory and the Harvard College Observatory’s programs. Today, the Harvard-Smithsonian Center for Astrophysics continues studies in astronomy, astrophysics, earth and space sciences, and science education, while the Harvard College Observatory supports Harvard’s Department of Astronomy.

The Boston Time Ball, which began operation in May 1878, was used to disseminate accurate time to the ships in Boston Harbor. The copper ball was four feet in diameter and was elevated onto a twenty foot pole on the roof of the Equitable Building on Milk Street; it could be seen from four miles away. The time signal to release the ball was relayed from the standard clock at Harvard College Observatory by telegraph wire to the ball. The service was especially important because accurate timekeeping was essential in determining longitude at sea.