Jantar Mantar Jaipur

This open air observatory is located outside the gateway of the City Palace Complex and is popularly known as Jantar Mantar, (where Jantra means instrument or device and Mantra stands for magic formula). It was built by the astronomer king Sawai Jai Singh II in 1728. Astronomy was a life-time obsession for the Maharaja, in the era when only few princes had the luxury of adequate instruments for knowing time. Sawai Jai Singh, the last classical astronomer of India, was ably supported and guided by Pandit Jagannat Samrat, whose immense knowledge and master by over various languages like Sanksrit, Arabic and Persian enabled Jai Singh to interpret various books, manuscripts and information related to astronomy and astrology from places, as far as Europe, Portugal, Greece and Britain. Astrological tables were prepared with the help of Pandit Keval Ramji.

Jantar Mantar is one of the five open-air astronomical observatories built by Jai Singh in the country. The first being at Delhi in 1724, followed by observatories at Jaipur (1728); Ujjain (1734); Varanasi (1737) and Mathura (1738). The observatory at Jaipur is the largest and most important of the five and is best preserved after the restoration work in 1901. The original brass instruments were replaced by masonry instruments used for measuring local time, the the altitudes of stars and constellations, the sun’s declination, meridian, altitude and determining eclipses are :

Laghu Samrat Yantra or the Small Sun :- Dial meant to show the solar time.

Samrat Yantra or the Big Sun Dial :- The triangular structure is the larger of the Laghu Samrat Yantra.

Dhruv Yantra or the Pol Star Instrument : - It is used at night to ascertain the position of the Pole Star and 12 zodiac signs, which are very helpful for various astrological calculations.

Raj Yantra or King of Instruments :- It is an astrolabe, which is used once a year for calculating the Hindu calendar, where all the details are based on Jaipur Standrad. The instrument has a big metallic disc of over 2 meter diameter, hanging over a wooden beam. There is a hole at the centre of the disc, which shows the position of the Pole Star.

Krantivritta Yantra or the Ecliptic Instrument : - The small instrument made of circular stone with an iron gnomon at its centre, is used for measuring longitude and latitude of the celestial bodies. It can be used during the day as well as at night.

Dish Yantra :- It points towards the northern direction.

Unnatansha Yantra :- It is used for finding the altitudes of the stars and planets.

Narivalaya Yantra :- The sun dials of the instrument are divided into two parts, one representing the northern while the other represents the southern hemisphere.

Dakshinovritti Bhitti Yantra :- It comprises of a vertical wall, which is aligned along the local N-S meridian and is used for interpreting the position and movement of the celestial bodies passing over the meridian.

Resivalaya Yantra or the Zodiac instrument :- It operates on the same principle as the Samrat Yantra but comprises of twelve sun-dials. Representing the twelve zodiac sings.

Jaiprakash Yantra :- It is used for observing the position of the sun, ascendants and other heavenly bodies and acts as a double check on all the other instruments of the observatory. It has been divided into two identical parts which work every hour alternately.

Chakra Yantra or the Circle Instruments :- This measures the angle of the celestial bodes from the equator.

Kapali Yantra :- It is divided into two hemispherical parts known as Kapali. The western Kapali as a prototype of the Jai Prakash instrument and represents the plane of the horizon. The eastern Kapali was used for solving astronomical problems graphically.

Ram Yantra :- It is made of circular walls and the floor graduated observing altitue and azimuth (arc of the celestial great circle from zenith to horizon) of the heavenly bodies. At the centre is a pillar, the shadow of which, indicates the local day time. The floor is also divided into sectors as in Jai Prakash Yantra.

Digansha Yantra :- It is yet another instrument which helps in calculating the azimuth of any heavenly body.