A Samrat Yantra was constructed at each of the observatories to provide precise measurement of time. The largest is at Jaipur, it’s gnomon rising to 22.6 meters (74 feet) The Samrat Yantra at Delhi is a close second at 20.7 meters (68 feet). The gnomon heights at Ujjain and Varanasi are 6.7 and 6.8 meters (22 and 22.3 feet).
The Jaipur and Delhi instruments could be read to an accuracy of 2 seconds, while those at Ujjain and Varanasi are accurate to within 20 and 15 seconds respectively.
The instruments at Jaipur and Delhi included Shasthamsa Yantras built within each of the structures that supported the quadrants.
At jantarmantar.org we have been modeling the Jantar Mantar instruments since the project began in 2003. Several architecture students created models based on measurements from Virendra Sharma, drawings from G.R. Kaye and Andreas Volwahsen, and our own panoramic photographs. The models and renderings in this gallery were created by Bei Xu, Cornell M.Arch 2017.
The Samrat Yantra at the Jaipur Observatory. A Samrat Yantra measures the time of day and declination of the sun.