About Jantar Mantar:
A unique structure raised in 1724, now lies in the heart of Delhi’s commercial center near Connaught Place. Maharaja Jai Singh II of Jaipur raised the Jantar Mantar, one of several astronomical observatories, as part of the five built by him. Mughal emperor Muhammad Shah tasked him with revising the calendar and astronomical tables. Someone placed a plaque on one of the structures in the Jantar Mantar observatory in New Delhi, mistakenly dating the construction of the complex to the year 1710. This occurred in 1910. Later research, though, suggests 1724 as the actual year of construction.
The primary purpose of the observatory was to compile astronomical tables and to predict the times and movements of the sun, moon, and planets. Some of these purposes nowadays would be classified as astronomy.