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Sun-Earth Day Presents: Ancient Observatories, Timeless Knowledge

Technology Through Time: Issue #27, Jantar Mantar


New Delhi, India
Latitude: 28 37', North. Longitude: 77 13'


The great Indian astronomer-king Maharaja Jai Singh II of Jaipur built these five astronomical observatories between AD 1724 and 1730 during the period generally known as the dark age of Indian history. He was inspired by the 15th-century Afghani ruler Ulughbek's observatory at Samarkand, They consist of brick and marble towers and pillars, with no telescopic elements at all, yet through solar shadow movements and careful sightings, the local time, and positions of the moon, stars and planets could be determined with great accuracy.


The Jantar Mantar consists of a number of masonry instruments for predicting time, measuring the position of a celestial body and determining the latitude. These instruments include the Brihat Samrat Yantra, the Rama Yantra and the Jai Prakash Yantra. The Brihat Samrat Yantra, is a huge sundial that gives the local time in New Deli very accurately. The Rama and Jai Prakash Yantras measure precise positions of celestial bodies in the night sky. When the sun is high in the sky, the pillar at the center of Rama Yantra casts a shadow either on the vertical well surrounding the pillar or the raised floor segments radiating from the pillar. These segments and the walls have fine graduations. The two pillars on the southwest of Mishra Yantra were designed to determine the shortest and longest days of the year. In December one pillar completely covers the other with its shadow while in June it does not cast any such shadow at all.



Image Gallery:


Photo Credit:

Vivek Dwivedi

Technology Through Time Bulletin Board Activity

This bulletin board activity is designed to focus student attention on the role that sun watching has played in humankind's survival through time. As part of this display you may wish to use your own world map ordownload one we have created for you.

Related Jantar Mantar Links