Litrelly Instruments for measuring the harmony of the heavens, the jantar mantar was built between 1728 and 1734. Jai singh wanted things on a grand scale and chose stone with a marble facing on the important planes. Each instrument serves a particular function each gives an accurate reading. Hindus believe that their fatted soiuls move to t he rhythem of the ihe universe and the matching of horoscopes is sttill an essential part in the selection partners for marriage. Astrologers are consuited for all imporatant decision-making. It gets extremely hot in the middle of the day.