Jantar Mantar

sights / Historic

Jantar Mantar information

Jaipur , India
Indian/foreigner ₹40/200, audio guide ₹150, human guide ₹200
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Adjacent to the City Palace is Jantar Mantar, an observatory begun by Jai Singh in 1728, which resembles a collection of bizarre sculptures. The name is derived from the Sanskrit yanta mantr meaning ‘instrument of calculation’, and in 2010 it was added to India’s list of World Heritage Sites.

Jai Singh liked astronomy even more than he liked war and town planning. Before constructing the observatory he sent scholars abroad to study foreign constructions. He built five observatories in total, and this is the largest and best preserved (it was restored in 1901). Others are in Delhi, Varanasi and Ujjain. No traces of the fifth, the Mathura observatory, remain.

Each construction within Jantar Mantar has a specific purpose, for example, measuring the positions of the stars, altitude and azimuth, and calculating eclipses. Paying for the half-hour to one-hour guide is worthwhile if you wish to learn how each fascinating instrument works and have questions.

Brihat Samrat Yantra

The most striking instrument is the Brihat Samrat Yantra (King of the Instruments) sundial, a massive edifice with a staircase running to the top. It has a 27m-high gnomonic arm set at an angle of 27 degrees – the same as the latitude of Jaipur. The shadow this casts moves up to 4m in an hour, and aids in the calculation of local and meridian time and various attributes of the heavenly bodies, including declination (the angular distance of a heavenly body from the celestial equator) and altitude. It’s still used by astrologers and is the focus of a gathering during the full moon in June or July, when it purportedly helps predict local monsoon rains, and subsequent success or failure of crops.

Laghu Samrat Yantra

If you tour the yantras in a clockwise direction, to the left as you enter the compound is the Laghu Samrat Yantra, a small sundial of red sandstone and white marble, inclined at 27 degrees. It does not measure as precisely as the Brihat Samrat Yantra, but does calculate the declination of celestial bodies, and the shadow cast by its gnomon enables local time (which differs from 10 to 40 minutes from Indian Standard Time) to be determined. On either side are two quadrants and local time can be determined by the shadow cast on each quadrant (one for the morning, one for the afternoon). Nearby is the Dhruva Darshak Yantra , used to find the location of the Pole Star and the 12 zodiac signs.

Narivalaya Yantra

The large circular object nearby, known as the Narivalaya Yantra, is actually two small sundials. The two faces of the instrument represent the northern and southern hemispheres, and enable calculation of the time within a minute’s accuracy.

Yantra Raj

Two large disks suspended from the wooden beams nearby comprise the Yantra Raj, a multipurpose instrument that, among other things, can help determine the positions of constellations and calculate the date of the Hindu calendar. A telescope is at the centre. The similar-looking Unnatansha Yantra lies in the northeastern corner of the observatory complex. This metal ring is divided into four segments by horizontal and vertical lines. A hole where these lines intersect, in the centre of the instrument, aids in the calculation of the altitude of celestial bodies. Nearby is Dakhinovrith Bhitti Yantra , which serves a similar function to the Unnatansha Yantra.

Rashi Yantras

West of the Brihat Samrat Yantra, near the southern wall of the observatory, you come to a cluster of 12 yellow instruments, the Rashi Yantras. Each rashi (individual instrument) represents one of the 12 zodiac signs. The gradient of each rashi differs in accordance with the particular sign represented and its position in relation to the ecliptic.

Jai Prakash Yantra

The Jai Prakash Yantra, resembling two huge slotted bowls, was the last instrument installed at the observatory and was invented by Jai Singh, after whom it was named. The instrument is used in celestial observations, but can also verify the calculations determined by other instruments at the observatory. Each of the two cavities is divided into six marble slabs, which are marked with minutes and seconds and with signs of the zodiac. The metal ring suspended in the centre represents the sun, and calculations can be made from the shadow cast by it on the marble slabs. This instrument may be used to calculate auspicious days for weddings, business negotiations and so on.

Kapali Yantra

The two other sunken concave structures in the western section of the observatory compound comprise the Kapali Yantra. The eastern Kapali Yantra is inscribed with lines to which astronomers refer in their deliberations, and is used for graphical analysis. The western Kapali Yantra is used to determine the position of a celestial body. Between the two bowls stands the Chakra Yantra , a pair of metal wheels, which can revolve parallel to the earth’s axis, and can be fitted with a brass tube in order to calculate the declination of celestial bodies.

Ram Yantras

Two other impressive instruments are the Ram Yantras, which look like miniature coliseums made of 12 upright slabs and 12 horizontal slabs. They are used in the calculation of the altitude and azimuth of celestial bodies. Between them is another circular instrument, the Digansha Yantra , with a pillar in the middle and two outer circles. It’s used for calculating azimuths, particularly of the sun. It can also be used to determine the time of sunrise and sunset.