Born Georgetown, District of Columbia, USA, 6 September 1811
Died Washington, District of Columbia, USA, 9 February 1865
James Gillis, son of George and Mary (née Melvile) Gillis, founded the United States Naval Observatory and served as its second superintendent. Gillis’ education in astronomy was largely self-directed. He was commissioned in the US Navy and served at sea before being assigned as a Lieutenant to the United States Navy Depot of Charts and Instruments. Working with limited resources from the depot, Gillis published the first star catalog based on American observations (1846).
Gillis began the process of ordering instruments for a first-class observatory, and then persuaded the US Congress that a new facility should be provided to house the instruments. Navy political considerations dictated the appointment of Matthew Maury as the first superintendent of the new observatory. Instead, Gillis was assigned for a period of time to the Coastal Survey working with Alexander Bache and Benjamin Peirce .
On his own initiative, Gillis persuaded the Navy and Congress to equip an expedition to Chile. The expedition’s goal was to make simultaneous observations of the oppositions of Mars and Venus from US observatories and from Chile. The intent was to improve upon the value of the solar parallax, or distance from the Earth to the Sun. Neither Harvard College Observatory director William Bond nor Maury assigned sufficient priority to the effort; therefore Gillis’s efforts fell short of a new determination of the solar parallax. The expedition, which was in Chile from December 1849 to September 1852, was otherwise quite productive, producing many useful measurements and a new catalog of southern celestial objects. The equipment left in Chile resulted in the establishment of Chile’s first astronomical observatory.
When Maury fled to the South and joined Confederate forces in the US Civil War, Gillis was promoted to Commander, and eventually Captain, and became the second Superintendent of the Naval Observatory in 1861. Gillis was a founding member of the United States National Academy of Sciences.