Jantar Mantar is situated in the heart of the capital city of Delhi, near Connaught Place. It is one of five astronomical observatories in India that was designed by Maharaja Sawai Jai Singh II. This monument was built in 1724 and has some of old-fashioned structures that are instruments for tracking the movement of celestial bodies.
These instruments are useful for measuring the position of stars, azimuth, altitude and calculation of eclipses. There is a Samrat Yantra at this site which reflects the accurate time within four minutes. The instrument named Jai Prakash is used for analysing the position of the sun and other heavenly bodies.