Maharaja Jai Singh II of Amber built Jantar Mantar in the year 1737. This is an observatory and happens to be one of the five observatories that were built by Maharaja Jai Singh II. It is situated on the roof of Man Mahala on Dashashwamedh Ghat Road and consists of a Samrat Yantra, DigamsaYantra, Cakra Yantra, Nadivalaya, and Daksinottara Bhitti Yantra.
Maharaja Jai Singh built five observatories across northern India namely Delhi, Jaipur, Ujjain, Varanasi and Mathura between 1724 and 1738. His decision to build multiple observatories at large distances from one another was in part a quest for accuracy; the ability to compare readings from different coordinates. It was also meant to strengthen the Maharaja’s political stature in regions where he had gained authority. It must also be mentioned that all the sites that Jai Singh chose have historical, political or religious significance.
The first to be built was the observatory at Delhi in 1724 and the last to be completed was the observatory at Jaipur in 1738. Of the five observatories, all but the observatory at Mathura still exist and are open for public viewing.
Sarnath - A Quest Within - Buddham Sharnam Gacchami