It is the brain-child of Maharaj Sawai Jai Singh II of Jaipur. Built in 1719 on Parliament St near Connaught Place, this manmandir or astronomical observatory ranks second only to the one in Jaipur. Solar and lunar movements and the Jantar Mantarmovements of other stars and planets can be observed from here. It is also a repository of time-measuring instruments. There are also Jantar Mantars at Ujjain, Varanasi and Mathura. It is open from sunrise to 22-00. Nearby is the Hanuman Temple.ome of the major instruments at Jantar Mantar are:

The Samrat Yantra 'Prince of Dials' (the largest device)
The Ram Yantra - two circular buildings
The Jai Prakash
The Misra Yantra (north-west to the Samrat Yantra)
Pillars on the southwest of Mishra Yantra used to measure the shortest and longest days of the year.
The Samrat Yantra measured the accurate time of the day. It also measured the declination of the sun which can be seen by the shadow moving around the structure.


The Jai Prakash shows the sun's position at the time of equinox. There is a hole near the bottom of the structure which witnesses sunshine only once in a year that is on 21 march, called vernal eqinox.


Another important structure called the Ram Yantra, consists of two large buildings with open top. Both these two buildings form a complete device. The device is used to measure the altitude of stars which is equivalent to the latitude and the longitude on the earth.


To the north-west of the Prakash Yantra, there is a structure or instrument called Mishra Yantra. It consists of five instruments. Pillars on the southwest of Mishra Yantra are used to measure the shortest day (21 December) and the longest day (21 June) of the year.

The samrat yantra consists of a massive triangle with a curved structure on both sides. The jaiprakash yantra is a two hemispherical bowl structure representing the celestial spheres and the use of a vertical rod in the center, giving different positions of celestial bodies during the day and night. The ram yantra is in the form of a high cylinder. It is surrounded by circular walls and the shadow of the sun on the vertical and horizontal marble gradations via the cylinder, indicates the altitude and the azimuth or declination of celestial bodies. The composite instrument is heart shaped and includes a sundial and a massive hemisphere on the northern wall. Sawai Jai Singh’s attempt to introduce a renaissance in astronomy through Jantar Mantar never took off due to chaos in the country. The first Indian Prime Minister Pandit Jawaharlal Nehru said that so accurate was his work that Jai Singh would have been remarkable anywhere. Thoroughly restored in 1901, the Jantar Mantar was declared a national monument in 1948.
All images copyright ©Terry Bowker, and may not be reproduced, including copying, transmitting, downloading, saving as a digital file, or linking to, without the written permission of the photographer.