jantar-mantar-history
Jantar Mantar is a heritage site that holds many astronomical instruments of yesteryear that are still in use. The Jantar Mantar is an equinoctial sundial, consisting a gigantic triangular gnomon with the hypotenuse parallel to the Earth's axis. The word Jantra is derived from yantra, instrument, while the suffix Mantar is derived from mantrana meaning consult or calculate. The words jantar and mantar (or yantra and mantra) mean calculation instrument. The instrument is intended to measure the time of day, correct to half a second and declination of the Sun and the other heavenly bodies. In the early 18th century, Maharaja Jai Singh II of Jaipur constructed five Jantar Mantars in total, in New Delhi, Jaipur, Ujjain, Mathura and Varanasi; they were completed between 1724 and 1735.

Jaipur has the largest Jantar Mantar with  a collection of nineteen architectural astronomical instruments built by the Rajput king Sawai Jai Singh II. It is a UNESCO World Heritage site and features the world's largest stone sundial. A sundial is a device that tells the time of day when there is sunlight by the apparent position of the Sun in the sky.  As the Sun appears to move across the sky, the shadow aligns with different hour-lines, which are marked on the dial to indicate the time of day.

Jantar Mantar Jaipur

Jantar Mantars were built for naked-eye observations of the celestial bodies and precision was achieved through their monumental dimensions. There are instruments working in each of the three main classical coordinate systems: the horizon-zenith local system, the equatorial system and the ecliptic system. Most significant instruments among the collection are Vrihat Samrat, Sasthamsa, Jai Prakash Yantra, Rama Yantra, Chakra Yantra, Rasivalaya, Kapala, Dingash Yantra, Unnatasha Yantra etc. Vrihat Samrat is probably the largest gnomon-sundial ever built which measures local time to an accuracy of 2 seconds. Sasthamsa has  four large meridian dials inside two high black chambers. A highly innovative sundial is Jai Prakash Yantra which is made of two hemispherical bowls that produce an inverse image of the sky and allow the observer to move freely around inside to take readings. Rama Yantra is rare and is a double-cylinder instrument to record the azimuth and altitude of celestial bodies. Rasivalaya is a unique group of 12 gnomon-dials to measure the ecliptic co-ordinates of celestial objects, each becoming operative when a different one of the 12 zodiacal constellations straddles the meridian. Chakra Yantra has four semicircular arcs on which a gnomon casts a shadow, thereby giving the declination of the Sun at four specified times of the day. It is equivalent of a wall of clocks registering local times in different parts of the world. Unnatasha Yantra is a metal ring divided into four segments by horizontal and vertical lines, with a hole in the middle. The position and orientation of the instrument allows measurement of the altitude of celestial bodies.

 Misra Yantra in Jantar Mantar, New Delhi

Misra Yantra in Jantar Mantar, New Delhi Jantar Mantar is located in the modern city of New Delhi. It consists of 13 architectural astronomy instruments. The site is one of five built by Maharaja Jai Singh II of Jaipur, from 1723 onwards. There are three instruments within the observatory of Jantar Mantar in New Delhi. These are Samrat Yantra, Jayaprakash Yantra, Misra Yantra. Jantar Mantar  was also  built in Varanasi in the year 1737. It is also located in the holy city of New Ujjain as the city is considered the Greenwich of India due to the fact that the first meridian of longitude in the Indian tradition passes through it. Moreover, it sits on the tropic of cancer.

                 Sun Dial at Ved Shala

 Jantar Mantar at Varanasi

Sun Dial at Ved Shala Jantar Mantar at Varanasi The instruments are in most cases huge structures. The scale to which they have been built has been alleged to increase their accuracy. Although the accuracy of reading is questionable, the astronomical structures are astonishing as they were made many centuries ago using brick, limestone and plaster. Best time to visit Jantar Mantar is throughout the year. Tourists are allowed to use the equipment to watch the heavenly bodies. Thus, clear days of summer or winter should be chosen. Moreover, visiting in the morning will help you explore the place in slow pace.