Jantar Mantar

Joshua Foer is a guest blogger on Boing Boing. Joshua is a freelance science journalist and the co-founder of the Atlas Obscura: A Compendium of the World's Wonders, Curiosities, and Esoterica, with Dylan Thuras.


Following up on Dylan's post about the Electrum, the world's largest Tesla Coil, I'd like to mention my own favorite super-sized scientific instrument: the Jantar Mantar astronomical complex in Jaipur, India. Constructed almost three centuries ago, its 73-foot-tall sundial is the largest in the world:

In 1728, Sawai Jai Singh II, rajah of Jaipur, dispatched his emissaries across the globe to gather the most accurate astronomical data possible. When they returned, Jai Singh ordered the construction of the Jantar Mantar complex, a monumental astronomical observatory constructed entirely out of stone and based on the astronomical tables of the French mathematician Phillipe de la Hire. Among the stone instruments Jai Singh constructed was the Samrat Yantra, a 73-foot tall sundial which remains the largest ever built. Though indistinguishable in design from other dials of the day, it was far and away the most accurate. Its two-second interval markings are more precise than even la Hire's table.

UPDATE: Uh oh. The picture above is of the Jantar Mantar complex in Delhi. Here's a photo of the one in Jaipur:


UPDATE TO THE UPDATE: Oy. That second picture, which I nabbed off Wikipedia, may still not be the right Jantar Mantar. This one, I am confident, is definitely the Jantar Mantar in Jaipur. Sorry for the confusion.