Jantar Mantar in Delhi is one of the five observatories built by the Maharaja of Jaipur - Sawai Jai Singh II. Maharaja Sawai Jai Singh II was also a noble in the Mughal court and a passionate astronomer. The Jantar Mantar was built to trace the astronomical phenomena and to ascertain scientific data from the same. The observatory in Delhi emphasizes the thirst for scientific knowledge of the Mughals. It is said that the Maharaja of Jaipur was disconcerted with the errors of the instruments in the observatory and took upon himself the feat of amending the errors and making the instruments accurate for recording astronomical phenomena. After the completion of Jantar Mantar, the observatory was functional for seven years. Data of each day was collected and charted and dedicated to the reigning emperor. The name ‘Jantar Mantar' is a colloquial form of the original terms ‘yantar'and ‘mantra'.