Jantar Mantar, Jaipur: Jai-Prakash Yantra!

In the previous post the Sun-Dial was shown, now I am psoting a photograph of a device known as "Jaiprakash Yantra" which was designed to determine in which Zodiac Sign the Sun was positioned at any given point of time. It is a wonderful device and a very interesting one too. In the photograph you can see a cylindrical structure with 12 pillars supporting a 'Ring' at the top. The shadow of this ring falling on a hemisphere inside the structure was used for reckoning the Zodiac.