Gaithersburg Latitude Observatory

The Gaithersburg Latitude Observatory is a historic astronomical observatory on DeSellum Avenue in Gaithersburg, Maryland. It was established in 1899 as part of a system of six International Latitude Observatories to precisely measure the wobble of the Earth's rotating axis. The observatory building and adjacent monuments were designated a National Historic Landmark in 1989 as a testament to international scientific cooperation. The observatory was taken out of service in 1982 after automation eliminated the need for human observations; the property is now owned by the city.

Observatory data from Wikidata (CC0). Summary from Wikipedia (CC BY-SA).