The Jantar Mantar – Oldest Observatory of India

Jantar Mantar, Jaipur


Jantar Mantar of Jaipur is largest and best preserved observatory out of five such built throughout the India. It is the modeled after the one that had built at Mughal capital of Delhi. The Jantar Mantar, Jaipur has been inscribed on World Heritage List as “an expression of astronomical and cosmological concepts of the court of a scholarly prince at the end of Mughal period”.

The term ‘Jantar Mantar’ is derived from the Sanskrit terms ‘Yantra‘ and ‘Mantra‘ meaning ‘instruments’ and ‘formula’ respectively. The term ‘Yantra’ was replaced with ‘Jantar’ which means ‘magical’. The name itself defines its significance kept with various astrological instruments.


Jantar Mantar was built by a Sawai Jai Singh Ji  in 18th century. It has a collection of astronomical and architectural instruments. The actual effort of structuring this building started in 1724 and continued till 1735. Jantar Mantar was made by Sawai Jai Singh as he was particularly interested in learning about the sky.As ancient Indian astronomers were Jyotishas so Jantar Mantar also has religious significance.

Jai Singh II (King of Amer) also built structures having astronomical features at different locations in India at Delhi, Ujjain, Mathura and Banaras (Varanasi).



Jantar Mantar Observatory has fourteen major geometric devices for measuring time, tracking locations of stars as earth revolves around the sun, predicting eclipses, determining the celestial altitudes & related ephemeride and ascertaining the declination of planets. Each tool present here is fixed and focused.

The structure is built from local stone and marble, each instrument carries an astronomical scale marked on inner lining of marble. Extraordinarily accurate Bronze tablets were also employed.

Jantar Mantar was restored in 1901 and was declared as national monument of India in 1948; after the independence of India in 1947.


Jantras (Instruments):

As total fourteen major instruments are present here, most of the instruments are the huge structures. Their accuracy is increased by the scale to which they have been built. The mesons constructing the instruments had no experience with construction of scale and this subsidence of foundation has subsequently misaligned them. For instance, the Samrat yantra can be used to tell the time to an accuracy of about two seconds in local time of Jaipur.

The Samrat Yantra (largest instrument) present here is 90 feet (27 m) high. It is employed to tell the time of day by plotting its shadow. Its face is angled at 27 degrees, which is latitude of Jaipur. The Samrat Yantra is also known as the Giant Sundial or Supreme Instrument is one of the world’s largest sundials. This equinoctial sundial consists of a gigantic triangular gnomon with its hypotenuse parallel to earth’s axis. And on both sides of gnomon is a quadrant of a circle which is parallel to plane of equator.

Another instrument, The Hindu Chhatri (small cupola) is placed on top which is used to announce eclipse and arrival of monsoon.


Jai Prakash Yantra (Credits :

Major instruments placed at Jantar Mantar are :

  • Laghu Samrat Yantra
  • Dhruva Darshak Pattika
  • Nadi Valaya Yantra
  • Palabha Yantra
  • Kranti Vritta Yantra
  • Yantra Raj Yantra
  • Unnantansh Yantra
  • Dakshinottar Bhatti Yantra
  • Vrihat Samrat Yantra
  • Shasthansh Yantra
  • Jai Prakash Yantra
  • Chakra Yantra
  • Kapali Yantra
  • Ram Yantra
  • Rashi Valaya Yantra
  • Digansh Yantra



Except all those importance of Jantar Mantar mentioned earlier, some religious significance is also there for local people of India. As in India for date of wedding, a very auspicious date is required; it is calculated by astrologers in this observatory. Astronomers and Jyotish scholars are also required to take lessons at this observatory.

  • It can be said that “observatory is the single most representative work of Vedic thoughts that still survives, apart from scriptures”.
  • Jaipur observatory was functional for seven years only.
  • UNESCO considered Jantar Mantar, Jaipur as World Heritage Site in UNESCO region South Asia under criteria III and IV of Cultural category.

The Jantar Mantar is a resplendent symbol of the imperial heritage of Jaipur and stands as a royal testimony to a former era. The magnificent structure still manages to capture the attention of tourists and astronomy enthusiasts as well. The Jantar Mantar is known to be a captivating structure and is a must visit place in Jaipur.

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