Gaithersburg Latitude Observatory

The Gaithersburg Latitude Observatory sits on DeSellum Avenue in Gaithersburg, Maryland, a quiet monument to a global scientific effort that once measured the very wobble of the Earth.

About Gaithersburg Latitude Observatory

Built in 1899, this small observatory was one of six International Latitude Observatories set up around the world at the same latitude, 39°8′ north, to precisely track variations in the Earth's rotational axis. Its work fed into a coordinated international dataset that is still valuable today for polar motion studies, climatology and satellite navigation.

History

The observatory used a reflecting telescope and a Photographic Zenith Tube to observe twelve groups of stars each night, recording tiny shifts in their positions to chart how the planet's axis drifts over time. It stayed in continuous service for over eight decades until 1982, when satellites and computers made human star observations unnecessary. In 1989 the building and its surrounding monuments were designated a National Historic Landmark in recognition of the international cooperation the project represented, and the site is now owned by the City of Gaithersburg.

Location & getting there

The observatory is located in Gaithersburg, Maryland, in the North America region, easy to combine with a visit to the surrounding historic district.

See your named star from here

While this observatory no longer makes nightly observations, its history of tracking star positions to sub-arcsecond precision is a fitting backdrop for anyone curious about the stars overhead. If you've named a star with Star Register, you can look up its exact coordinates in our catalogue and find it with a telescope or stargazing app from anywhere, including a clear night near Gaithersburg.