Jantar Mantar is the biggest of five astronomical observatory build by Maharaja Jai Singh during the period 1727-1734 in north India. It is located very close to the City Palace. The observatory consists of fourteen major geometric devices (or yantra in Hindi) for measuring time, predicting eclipses, tracking stars in their orbits, ascertaining the declinations of planets, and determining the celestial altitudes etc. Unfortunately no text is made available to tourists regarding the various yantras nor are there any plaques/boards in front of them. In most of the cases local guides are not of any help either..



The Samrat Jantar, the largest instrument, is 90 feet high, its shadow carefully plotted to tell the time of day. Its face is angled at 27 degrees, the latitude of Jaipur. The Hindu chhatri (small domed cupola) on top is used as a platform for announcing eclipses and the arrival of monsoons.Built of local stone and marble, each instrument carries an astronomical scale, generally marked on the marble inner lining; bronze tablets, all extraordinarily accurate, were also employed. Thoroughly restored in 1901, the Jantar Mantar was declared a national monument in 1948.>