Jai Prakash Yantra is a two hemispherical bowl-based sundial with marked marble slabs that map inverted image of sky and allows the observer to move inside the instrument, measures altitudes, azimuths, hour angles and declinations.

This is part of the Jantar Mantar monument that is a collection of nineteen architectural astronomical instruments, built by the Rajput king Sawai Jai Singh II, and completed in 1734. It features the world's largest stone sundial. [Wikipedia]