The Ladd Observatory was built in 1891 by Brown University, and features the original telescope over 130 years old. The telescope is one of only a handful of large refractor telescopes from that era. At the time of its construction, the observatory was located at the highest point in Providence (shifts in the city’s borders eventually caused this to be the city’s second-highest point.) The hilltop was a rural area with minimal light pollution. However, in the decades after the observatory was built, the area was built up into Providence’s Hope neighborhood, making for brighter night skies at Ladd.
The telescope runs completely mechanically, there are no electric components. Aside from replacing a few ropes and cables, the entire telescope is original. The telescope features an ingenious system of weights—it is wound up each night with a clockwork mechanism, and a series of weights fall throughout the night, calibrated in sync with the earth’s rotation. This mechanism causes the telescope to rotate at the same rate as the Earth, giving observers a stable view of the universe. The observatory was initially used for both research and teaching Brown University students. In addition to teaching astronomy and physics, the Ladd was used to teach celestial navigation during the World Wars.
In addition to being an observatory, Ladd offered a regional timekeeping service until 1973. The timekeeping instruments can still be seen on the ground floor of the Ladd Observatory, kept under exact conditions (sealed in a room with stable temperature, pressure, and humidity, and free of ambient vibration.)