The Leiden Observatory, located at Sterrewachtlaan 11 (and on the Witte Singel), was built in 1633 as the observatory of Leiden University, making it the oldest university observatory in the world. For its first two decades, the observatory was primarily used for educational purposes. In 1861, a new and larger observatory was built under the direction of Frederik Kaiser, now known as the "Oude Sterrewacht."
The Leiden Observatory has had many world-renowned directors, including Frederik Kaiser, Willem de Sitter, Ejnar Hertzsprung, and Jan Hendrik Oort.
Other famous astronomers who worked at the observatory included Hendrik Antoon Lorentz, Jacobus C. Kapteyn, and Hendrik Christoffel van de Hulst. The current director is Ignas Snellen (since 2022). (Source: Wikipedia)
In 1974, the astronomers moved into the new buildings of the Bioscience Park. The Oude Sterrewacht was then used as a temporary building for various university groups. After a thorough restoration (2009-2011), the building is now used by the Faculty of Law. The telescopes and domes are used by students and volunteers, who open them to the public during special open days, lectures, and tours. (Source: visitleiden.nl)