Jantar Mantar, Jaipur

The story of Jantar Mantar, Jaipur

Jantar Mantar, Jaipur is a collection of 19 astronomical instruments, and its most striking feature is the world’s largest stone sundial. Built by the Rajput king Sawai Jai Singh, the founder of Jaipur, the monument was completed in 1734 and spread over about 18,700 square metres.

The name Jantar Mantar comes from two Sanskrit words: jantar from yantra, meaning “instrument, machine,” and mantar from mantrana, meaning “consult, calculate.” Taken together, the name means “calculating instrument,” which suits a place designed for measuring the sky. The observatory allows astronomical positions to be observed with the naked eye, and it is an example of the Ptolemaic positional astronomy shared by many civilizations.

The instruments here operate in each of the three main classical celestial coordinate systems: the horizon-zenith local system, the equatorial system, and the ecliptic system. One instrument, the Kanmala Yantraprakara, works in two systems and allows coordinates to be transformed directly from one system to the other. Built from local stone and marble, each instrument carries an astronomical scale, generally marked on the marble inner lining, and bronze tablets, bricks and mortar were also used.

Construction in Jaipur was underway by 1728, though exactly when Sawai Jai Singh began it is unknown. During 1735, when work was at its peak, at least 23 astronomers were employed in Jaipur, and the city replaced Delhi as Jai Singh’s main observatory. The observatory remained his central observatory until his death in 1743.

Its later history includes decline and repair. It lost support under Ishwari Singh after a succession war, then received support again under Madho Singh I, although not at the same level of activity. Some restorations were made under Pratap Singh, and the observatory was restored again several times during the British Empire, particularly in 1902. Early restoration work was supervised by Major Arthur Garrett, an amateur astronomer who served as Assistant State Engineer for the Jaipur District. The monument was damaged in the 19th century, fell into disuse and disrepair after about 1800, was declared a national monument in 1948, restored in 2006, managed under the Archeological Sites and Monuments Act of Rajasthan since 1961, and protected as a National Monument of Rajasthan since 1968. UNESCO describes it as the most significant and best-preserved historic observatory in India, and it became a World Heritage Site in 2010.

It stands within City Palace, Jaipur, near City Palace and Hawa Mahal. When you visit, the scale of the instruments and the marble-lined surfaces are among the details to look for.