The Jantar Mantar in Jaipur, Rajasthan is an astronomical observation site built in the early 18th century, which includes a set of around 20 main fixed instruments. Designed for the observation of astronomical positions with the naked eye, they embody several architectural and instrumental innovations. A UNESCO World Heritage Site, it is considered the most significant, most comprehensive, and the best preserved of India’s historic observatories. It is an expression of the astronomical skills and cosmological concepts of the court of a scholarly prince at the end of the Mughal period. Through the impetus of its creator, prince Jai Singh II, the observatory was a meeting point for different scientific cultures, and gave rise to widespread social practices linked to cosmology.