Between 1727 and 1734 Maharajah Jai Singh II of Jaipur constructed five astronomical observatories in west central India.The observatories, or "Jantar Mantars" as they are commonly known, incorporate multiple buildings of unique form, each with a specialized function for astronomical measurement. These structures with their striking combinations of geometric forms at large scale, have captivated the attention of architects, artists, and art historians world wide, yet remain largely unknown to general public.
The name is derived from yantra, instrument, and mantra, for formula or in this context calculation. Therefore jantar mantar means literally calculation instrument.The yantras have evocative names like, samrat yantra, jai prakash, ram yantra and niyati chakra; each of which are used to for various astronomical calculations.The primary purpose of the observatory was to compile astronomical tables, and to predict the times and movements of the sun, moon and planets.
Jantar Mantar presents the observatories through a variety of media and information sources, making it possible to explore and learn about these historic sites through interactive panoramic "VR" photographs, time lapse sequences, and 3D models as well as articles, drawings, and historic texts. It is a comprehensive resource for exploring the observatories in depth.
Jantar Mantar has a remarkable collection of architectural astronomical
instruments..It portrays noteworthy attempt of the ancestors, who were interested in astronomy and knowledge of celestial bodies. Above all, this observatory still, provides accurate information, which can be compared with today's modern instruments undeniably. The compound
instruments, whose settings and shapes are scientifically designed depicts the forte of Medieval Indian Astronomy.
The observatory consists of fourteen major geometric devices for measuring time, predicting eclipses, tracking stars in their orbits, ascertaining the declinations of planets, and determining the celestial altitudes and related ephemerides. Each is a fixed and 'focused' tool. . Observation deck of the samrat yantra (Giant sundial).
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.An excursion through Jai Singh's Jantar is the singular one of walking through solid geometry and encountering a collective astronomical system designed to probe the heavens.
The instruments are in most cases huge structures. .They are built on a large scale so that accuracy of readings can be obtained. The samrat yantra, for instance, which is a sundial, can be used to tell the time to an accuracy of about two seconds in Jaipur local time. It is considered the largest sundial in the world.The Giant Sundial, known as the Samrat Yantra (The Supreme Instrument) is the world's largest sundial, standing 27 meters tall. Its shadow moves visibly at 1 mm per second, or roughly a hand's breadth (6 cm) every minute. .Today the main purpose of the observatory is to function as a tourist attraction.