Jantar Mantar ![]() This is the most significant, most comprehensive, and the best preserved of India's historic observatories. It is an expression of the astronomical skills and cosmological concepts of the court of a scholarly prince at the end of the Mughal period. The largest example is the equinoctial sundial belonging to Jaipur's assembly of instruments, consisting of a gigantic triangular gnomon with the hypotenuse parallel to the Earth's axis. On either side of the gnomon is a quadrant of a circle, parallel to the plane of the equator. The instrument can be used with an accuracy of about 2 seconds by a "skilled observer" to measure the time of day, and the declination of the Sun and the other heavenly bodies. It is the world's largest stone sundial, known as the Vrihat Samrat Yantra. By the close of the nineteenth century, it had fallen into ruin. In 1901, Maharaja Ram Singh embarked on the restoration and reconstruction of the observatory. The Jaipur Jantar Mantar is a UNESCO World Heritage Site. |