The marvel that is Jaipur's Jantar Mantar

In the middle of the city, in Jaipur, stands the world’s largest stone sundial in one of the largest astronomical observatories in the world – Jantar Mantar, Jaipur. Built in 1734 by the Rajput Maharaja Sawai Jai Singh II, Jantar Mantar is one of the finest examples of Ptolemaic positional astronomy.

This large observatory has a collection of many stone structures (known as instruments) that help calculate time and interpret the position of the celestial bodies. Jantar Mantar is a scientific and an architectural marvel; it is known for its perfection. Jaipur's Jantar Mantar is also a UNESCO World Heritage Site

Maharaja Sawai Jai Singh built five such observatories across India – Jaipur, Delhi, Mathura, Ujjain and Varanasi. The one in Mathura is in ruins now.


What makes the Jantar Mantar such an amazing attraction? The observatory comprises 19 stone instruments of interesting shapes and sizes, all to measure positions of extraterrestrial bodies.



The centre of the Jantar Mantar has a tall sundial – Vrihat Smarat Yantra – measuring a height of 27 m, making it the world’s tallest sundial. The instrument’s precision is worthy of praise. It measures time up to the precision of two seconds! A smaller sundial, called Laghu Smarat Yantra, has a ramp that points towards the North Pole; so if you were to calculate Jaipur time, you can look at the ramp’s shadow on the fine divisions carved on a scale next to it.


The shadow of the triangular wall of the device will help you know the local time. Still following?

The Ram Yantra – this structure tells you the direction of the Sun and other planets with the help of poles of equal height at the centre, and scales inscribed in the interior walls of the structure. Then, there is Jaya Prakash Yantra that consists of two hemispherical marble bowls. When the inverted image of the sky falls on the structure, it gives the exact position and elevation (among many other things) of the planets and other heavenly bodies! Exact!


Another such fascinating instrument is the Digamsa, a pillar, with the help of two concentric outer circles, which helps predict sunrise and sunset. Go figure.


For someone fueled by memes, I can’t help but ask, “but how did they know?”. If you are as stunned and fascinated as I am, maybe you need to go see the observatory for yourself.

1. How many Jantar Mantars are there in India?
   There were a total of five – Jaipur, Delhi, Ujjain, Varanasi and Mathura. At present, only four remain. The Mathura Jantar Mantar is in ruins now.
2. What is the best time to visit Jaipur Jantar Mantar?
   Noon. When the sun is vertically above you, that’s when it is the best way to understand the interpretation.
3. Is there an entry fee?
   For Indians INR 50 per person; INR 15 per person for Indian students; INR 100 per person for foreign students; INR 200 per person for foreign tourists.