Jantar Mantar, Jaipur: Old Era Observatory!

Janatar - Mantar is located at the heart of the city of Jaipur, Rajasthan, beside the City Palace! It is, in fact, a collection of a number of structures and instruments built by Sawai Jai Singh. The Maharaja had a great interest in Astronomy and had scholars who were experts in Astronomy and mathematics. He himself had a great deal of knowledge of the subject -- as a result he wanted to make use of his knowledge to understand the positioning of the various planets and stars. 

The two photographs posted below shows show the Sun-Dial built by Sawai Man Singh to find the time, based upon the shadow of a structure on the Sun-Dial. It functions during the day only and that too when there is Sunshine.

There is a staircase at the center with two Dials, one on the left and the other one on the right. The shadow of the Staircase falls on the 

1) Sun-Dial on the left, from Sunrise to noon.

2) Sun-Dial on the right, noon to Sunset. 

There are markings on the Sun-Dials which are counted, as per position of the shadow, to find the time at any given point. The accuracy of the measurement is within 1/2 (half) a min.