Edward Singleton Holden (1846-1914): His career at the U. S. Naval Observatory from 1873 to 1881

Edward Singleton Holden (1846-1914) held many positions during his career, including: astronomer at the U. S. Naval Observatory, Director of Washburn Observatory, President of the University of California, Director of Lick Observatory, and finally, Librarian at West Point. This presentation covers his tenure at the Naval Observatory. Educated at Washington University under Chauvenet, he went on to further study at West Point, graduating 3^rd in his class in 1870. He resigned his commission in the Army in 1873 to become an astronomer at the Naval Observatory. He first assisted William Harkness on the transit circle and then Simon Newcomb took an interest in him and became an early mentor. When the 26-inch Clark refractor was completed in 1873, Holden was assigned to assist Newcomb. In 1875 Asaph Hall took over the 26-inch and Holden continued in this position. One of Holden's major accomplishments at the Observatory was the publication of the Monograph of the central parts of the nebula of Orion in 1882. He meticulously gathered all images of the central part of the nebula known at that time, beginning with a drawing by Huygens in 1656. These images, which were later used in the published volume, are mounted in a manuscript book held in the Observatory Library. Holden thought the relative brightness of certain parts of the nebula changed over time and tried to verify this theory. However, in 1882, his friend Henry Draper took a photographic image of the nebula with an exposure of 137 minutes which Holden readily accepted and included in the monograph. He immediately realized that photography was the tool of the future and would give a reliable, permanent record that later did indeed prove his theory was incorrect. Holden's work in the libraries of the Naval Observatory and West Point will also be discussed.