Georgetown University Astronomical Observatory

The third observatory founded in the United States, this building was part of pioneering work in astronomy.

Georgetown University's Greek Revival astronomical observatory is located on a knoll in the southwest corner of the campus, south of Kehoe Field and north of McDonough Memorial Gym. The observatory is the third oldest in the United States. It was planned and supervised by Father James Curley, a self-taught mathematician.

Construction took place between 1841 and 1844 when its first instrument arrived at the observatory. At the time, there were only two other such installations in the country. After securing the services of Father John Hagen in 1888, the observatory was renovated and a new equatorial telescope purchased, enabling important research on the earth’s rate of rotation, which Hagen published in his Synopsis while at Georgetown.

Lack of interest in an astronomy department and the impracticality of a giant telescope near the city, considering the glare from Washington's nighttime lights, eventually led to the observatory falling into disuse. The building was later repurposed as storage for Potomac River water samples for the Biology Department. The observatory is maintained today by the Georgetown University Astronomical Society.

DC Inventory: November 8, 1964 (Joint Committee on Landmarks)
National Register: July 2, 1973
Within Georgetown Historic District



Heyden Memorial Garden, West Road