Celebrating Spring Equinox with a Workshop on Astrolabes
On March 20, 2025, Stanford’s History Department celebrated the spring equinox by hosting a hands-on workshop on astrolabes—ancient astronomical instruments invented in ancient Greece, widely used in the Islamic world during the medieval and early modern periods, and later adopted in Western Europe before gradually losing popularity by the 17th century. The event was sponsored by Stanford’s program in History and Philosophy of Science.
The workshop was conducted by Federico Cortigiani, a fourth-year History Phd researching the history of science and environment in the early modern Ottoman Empire, and Fyza Parviz Jazra, a first year History Phd in the field of History of Science, who works on astronomical knowledge exchange between Western Europe and the Islamic world in the early modern era.
The workshop began with a brief historical overview of astrolabes, highlighting not only their significance in the history of science and technology but also their impact on art and material culture. Astrolabes serve as a prime example of how material culture traversed continents throughout history. These instruments had a range of uses, including navigation, timekeeping, surveying, and even astrology.
The audience also had the opportunity to hold and examine two brass astrolabe instruments—one inscribed in Latin and the other in Arabic.
For much of the workshop, participants assembled astrolabe paper kits. They learned about the various components of these instruments and their respective functions before practicing how to read specific values on the device. They then received a handout with detailed instructions on measuring the sun’s elevation above the horizon, calculating Stanford’s latitude, and determining the time.
Moving outside to the balcony of the History building, the attendees carefully conducted their measurements. They had to maintain steady hands while holding the instrument to measure the sun’s shadow on paper accurately. These exercises illustrated the painstaking effort astronomers once invested in deriving data that is now instantly accessible on smartphones. Still, there was a shared sense of excitement when the latitude and time calculations turned out to be surprisingly precise.
The workshop drew a diverse group from the Stanford community, including undergraduates, graduate students, part-time students, and staff. Graduate students came from a range of disciplines within the History department, as well as from other departments such as Classics. Overall, the participants were delighted to learn how to use an ancient astronomical instrument.
