At first glance it looks like a modern sculpture garden. Once you get close to these large calculation devices and with the help of a good guide their construction and accuracy will amaze you. You can see prototypes of each device and the still-accurate final instruments made of sandstone, marble and bronze. The Jai Prakash Yantra (above) was used in calculating celestial observations and tracking the signs of the zodiac. Jai created instruments for calculating the exact angle of the sun, positions of constellations (by calendar day and hour), and Calendar day. My favorite are his time pieces - two large sundials. The smaller of the two, which is about 15 feet tall, is accurate to 20 seconds...The large sun dial is 27 meters tall. It can calculate the time to 2 seconds - and it is nearly 300 years old!