Sproul Observatory

Sproul Observatory is an astronomical observation facility located on the Swarthmore College campus in Pennsylvania. The site housed a large refracting telescope inside a white domed building that served both research and educational purposes for the college.

The facility was founded in 1907 through funding by William Cameron Sproul, a former Pennsylvania governor and college graduate. Operations continued from 1913 until 2017, when the telescope was relocated to continue scientific outreach work elsewhere.

This facility served as a center for astronomy education at the college, where students could observe the night sky and conduct their own research directly. The site represented hands-on learning in science rather than purely theoretical classroom instruction.

The site is located on the Swarthmore College campus and is no longer operational today. Visitors can see the white dome structure, but should know that the telescope and active research have been relocated elsewhere.

Researchers working under Peter van de Kamp used photographic plates from the telescope to track how stars move through space over time. These observations provided early evidence for the existence of planets orbiting distant stars decades before direct detection methods became possible.

Location: Pennsylvania

GPS coordinates: 39.90310,-75.35530

Latest update: December 13, 2025 17:00