Discover India's Jantar Mantar

What Is Jantar Mantar?

Jantar Mantar in Jaipur is the largest and best-preserved of five astronomical observatories built by Maharaja Sawai Jai Singh II between 1724 and 1735. UNESCO inscribed it as a World Heritage Site in 2010, recognizing it as an outstanding example of the meeting of scientific and architectural traditions (source: UNESCO World Heritage List).

The site contains 19 astronomical instruments, some reaching over 27 meters in height, each designed for a specific astronomical observation. Jai Singh II, himself a scholar and astronomer, was dissatisfied with the accuracy of brass instruments of his era and commissioned these monumental stone instruments to achieve greater precision.

What Are the Key Instruments?

The Samrat Yantra (Supreme Instrument) is the site’s centerpiece and the world’s largest stone sundial. Its gnomon (triangular structure) stands 27 meters tall, aligned precisely with the Earth’s axis, and casts a shadow that moves approximately 1 mm per second. It can determine local solar time to an accuracy of approximately 2 seconds (source: ASI).

The Jai Prakash Yantra consists of two hemispherical bowls set into the ground, representing inverted maps of the sky. A suspended ring casts a shadow onto the carved marble surface, allowing observers to determine the position of the sun and other celestial bodies.

The Ram Yantra is a pair of cylindrical structures with open tops used for measuring the altitude and azimuth of celestial objects. The Rashivalaya Yantra is a collection of 12 instruments, each aligned to one of the 12 zodiac signs, used for calculating celestial positions.

How Should You Plan Your Visit?

Jantar Mantar sits adjacent to City Palace and a 5-minute walk from Hawa Mahal. Our guides typically visit all three together in the late morning during the Jaipur day tour and the Golden Triangle tour.

We cannot overemphasize the value of a guide at Jantar Mantar. Without explanation, the instruments appear to be monumental abstract sculptures. With a knowledgeable guide, the site transforms into a hands-on science lesson — our guides demonstrate how each instrument works using real-time shadow readings, making this one of the most intellectually engaging attractions in Jaipur.

The site is compact and flat, making it accessible for most visitors. Midday visits offer the most dramatic sundial demonstrations when the sun is high and shadows are sharp and well-defined.