Jaipur, India. Jantar Mantar. The Jantar Mantar, Jaipur, is an astronomical observation site built in the early 18th century. It includes a set of some twenty main fixed instruments reach having specific characteristics. The Jantar Mantar is an expression of the astronomical skills and cosmological concepts of the court at the end of the Mughal period. Designed for the observation of astronomical positions with the naked eye, they embody several architectural and instrumental innovations. The observatory forms part of a tradition of Ptolemaic positional astronomy which was shared by many civilizations.