The Jantar Mantar is an astronomical observation site built at the beginning of the 18th century in Jaipur. It includes a set of about 20 main fixed instruments. They are the monumental examples in masonry of known instruments but in many cases they have their own specific characteristics. Designed for the observation of astronomical positions with the naked eye, they incorporate several architectural and instrumental innovations. This is the most important, most complete and best preserved historical observatory in India. It is an expression of the astronomical abilities and cosmological concepts of the court of a learned prince at the end of the Mughal period.

in Jaipur The Jantar Mantar observatory is the most significant and best-preserved ensemble of fixed monumental instruments built in India in the first half of the 18th century.Few of them are the largest ever built in their categories. Designed for the observation of astronomical positions with the naked eye, they incorporate several architectural and instrumental innovations. The observatory is part of a tradition of positional Ptolemaic astronomy that was shared by many civilizations. He contributed with this type of observation to the completion of Zij's astronomical tables. It is a late and final monumental culmination of this tradition.

Thanks to 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 related to cosmology. It was also a symbol of real authority, through its urban dimensions, its control of time and its capacities for rational and astrological forecasting. The observatory is the monumental incarnation of the union of needs that were at the same time political, scientific and religious.