Place · observatory · India
Jantar Mantar, Jaipur
Nineteen masonry instruments built by Jai Singh II from 1734 inside his own new city, including the twenty-seven-metre Samrat Yantra, the largest stone sundial in the world, and a separate instrument for each sign of the zodiac. They were built to correct the planetary tables in use by direct observation rather than to teach.
- Function
- Science & medicine
- Confidence
- Established / referenced
- Location
- 26.925, 75.824
Worth knowing
Jai Singh compared his instruments against Ptolemy's tables and Ulugh Beg's, found both wanting, and built in masonry rather than metal because bigger instruments read finer. The Samrat Yantra sundial resolves time to about two seconds.
Connections (4)
- Site adjacencyJaipur walled city
Jai Singh laid out Jaipur in 1727 on a nine-square grid derived from shastraic town planning and put his observatory inside it, a few hundred metres from the palace. The two are one project: a ruler who was also a working astronomer building a city on a theoretical plan and an instrument to correct the planetary tables by direct observation. Almost nothing else in Indian history combines those two things in one patron.
- Architectural modelJantar Mantar, Delhi
Jai Singh built Delhi's Jantar Mantar first, in 1724, and then found its instruments too small for the accuracy he wanted; the Jaipur observatory of 1734 corrects that with larger versions of the same devices, including a sundial twenty-seven metres high that reads to two seconds. The sequence is visible as an engineering progression across five sites, which is why the set matters more than any one of them.
- PatronageSawai Jai Singh II
Jai Singh II built five observatories, of which Jaipur's is the largest and best preserved, and had Ptolemy, al-Tusi and the Siddhantas read side by side against his own observations. He also planned the city the observatory stands in, on a grid taken from the shastras. The same ruler produced the most mathematical Indian city and the most accurate masonry instruments ever built.
- Site withinJaipur
Jantar Mantar, Jaipur sits inside Jaipur and forms one piece of its layered sacred, royal or civic landscape. The city carries this entry as one of the sites that make its urban fabric legible — a shrine, monument, institution or craft tradition specifically anchored at this location — and the city's broader history reads better when the stop is seen in its context rather than in isolation. The surrounding streets, markets and other heritage ensembles around it belong to the same single city.
On these journeys
Sources
Wikipedia, “Jantar Mantar, Jaipur”. UNESCO World Heritage nomination file for the Jantar Mantar, Jaipur (2010); Virendra Nath Sharma, Sawai Jai Singh and His Astronomy (1995).
Open Jantar Mantar, Jaipur in the repository →