Jantar Mantar Jaipur: Improved Sun-Dial

Jantar-Mantar --- let's decode the name, the name is derived from the Hindi words Jantar which means instrument and Mantar which means calculation or a formula.   

The photograph posted shows the Sun-Dial, a device built to indicate local time during the daytime i.e. Sunrise to Sunset since the functioning of the instrument is based upon the shadow of a triangular Structure falling on the Sun-Dial. What you see in the photograph on the left is a staircase which is in fact a triangular structure (see the pic on the right) , the staircase is just to go up to the top of the device. The shadow of the triangular structure falls on the semicircular dial, which is used for calculating the local time at any given point during the day. The Sun-Dial is accurately graduated (has markings) to enable any observer to find out the time.