The Jantar Mantar in the capital city of Delhi is a living example of ‘classical Indian astronomical study’. Erected by the great Rajput builder, Raja Sawai Jai Singh, in the early eighteenth century, this remarkable stone observatory is a favorite attraction among tourist in the city. The observatory is the first of its kind to be built with large masonry instruments that include the Samrat Yantra (a huge sundial), the Ram Yantra, Misra Yantra and other instruments. It is a wonderful experience to unfold the mysteries of celestial world with the age-old formulae of Jantar Mantar, once the primary astronomical center of the Royals.

Dissatisfied by the errors of brass and metal astronomical instruments, a great astronomer king and a noble in the Mughal court set out to rectify the existing planetary observations with the help of more reliable instruments. His intent endeavor to make the calculations agree with observations with large masonry instruments fructified in the form of the famous Jantar Mantar of Delhi. Today due to the invention of more sophisticated and scientifically enriched equipment, this stone observatory is not in used, but one can still calculate the exact time and moment with absolute perfection by carefully going through the functions of every instrument here.

The gigantic sundial of the observatory, Samrat Yantra, is meant to calculate the exact time of the day. It consists a huge gnomon with hypotenuse parallel to the Earth’s axis. There is a quadrant of a circle parallel to the plan of the equator on either side of the gnomon. Another major instrument is the Ram Yantra. It contains two circular structures with a pillar at the center of each circle. The instrument is used for reading horizontal angles of celestial bodies. Again the Jai Prakash Yantra is used to detect the position of the Sun, the local time and sign of the Zodiac. The Misra Yantra is a combination of four scientific gadgets- the Niyata Chakra (in the center), part of the Samrat Yantra on its either side, Dakshinottara Bhitti Yantra (for obtaining meridian altitude) and Karka Rasi Valaya (indicating the entry of the Sun).