Jantar Mantar (literally meaning ‘calculation instrument’) is located in the modern city of New Delhi. It consists of 13 architectural astronomy instruments. It was constructed in 1724 by Maharajah Jai Singh II of Jaipur who was given the task of revising the calendar and astronomical tables by Mughal emperor Muhammad Shah .
The primary purpose of the observatory was tocompile astronomical tables, and to predict the times and movements of the sun, moon and planets.
There are three instruments within the observatory of Jantar Mantar in New Delhi: the Samrat Yantra, the Jayaprakash Yantra, and the Misra Yantra.
- The Samrat Yantra, or Supreme Instrument, is a giant triangle that is basically an equal hour sundial. It is 70 feet high, 114 feet long at the base, and 10 feet thick. It has a 128-foot-long (39 m) hypotenuse that is parallel to the Earth’s axis and points toward the North Pole. On either side of the triangle is a quadrant with graduations indicating hours, minutes, and seconds. At the time of the Samrat Yantra’s construction, sundials already existed, but the Samrat Yantra turned the basic sundial into a precision tool for measuring declination and other related coordinates of various heavenly bodies.
- The Jayaprakash Yantra consists of hollowed out hemispheres with markings on their concave surfaces. Crosswires were stretched between points on their rim. From inside the Ram, an observer could align the position of a star with various markings or a window’s edge.
- The Misra Yantra was designed as a tool to determine the shortest and longest days of the year. It could also be used to indicate the exact moment of noon in various cities and locations regardless of their distance from Delhi – quite remarkable!
Sadly, accurate observations can no longer be made from here because of the tall buildings of New Delhi obscuring continual access to the sun by the observatory.
Photo credits: Beverley Bloxham