JANTAR MANTAR , JAIPUR
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The Jantar Mantar monument of Jaipur, Rajasthan is a collection of nineteen architectural astronomical instruments, built by the Rajput king Sawai Jai Singh, and completed in 1738 CE. It features the world's largest stone sundial, and is a UNESCO World Heritage site.
Located near City Palace and Hawa Mahal of Jaipur, the monument features masonry, stone and brass instruments that were built using astronomy and instrument design principles of ancient Hindu Sanskrit texts. The instruments allow the observation of astronomical positions with the naked eye. The monument expresses architectural innovations, as well as the coming together of ideas from different religious and social beliefs in 18th century India. The observatory is an example of the Ptolemaic positional astronomy which was shared by many civilizations.
The monument features instruments operating in each of the three main classical celestial coordinate systems: the horizon-zenith local system,Kapala Yantraprakara is one that works in two systems and allows transformation of the coordinates directly from one system to the other.
The monument was damaged in the 19th century. Early restoration work was undertaken under the supervision of Major Arthur Garrett, a keen amateur astronomer, during his appointment as Assistant State Engineer for the Jaipur District.The name is derived from jantar, and mantar Therefore Jantar Mantar literally means 'calculating instrument'.The Vedas mention astronomical terms, measurement of time and calendar, but do not mention any astronomical instruments. The earliest discussion of astronomical instruments, gnomon and clepsydra, is found in the Vedangas, ancient Sanskrit texts. The gnomon found at Jantar Mantar monument is discussed in these 1st millennium BCE Vedangas and in many later texts such as the Katyayana sulbasutras. Other discussions of astronomical instruments are found in Hinduism texts such as the 4th century BCE Arthashastra, Buddhist texts such as Sardulakarna-avadana, and Jainism texts such as Surya-prajnapti. The theories behind the instruments are found in texts by the 5th century CE Aryabhatta, 6th century CE Brahmagupta and Varahamihira, 9th century Lalla, 11th century Sripati and Bhaskara. The texts of Bhaskara have dedicated chapters on instruments and he calls them Yantra-adhyaya.
The theory of chakra-yantra, yasti-yantra, dhanur-yantra, kapala-yantra, nadivalaya-yantra, kartari-yantra and others are found in the ancient texts.Built from local stone and marble, each instrument carries an astronomical scale, generally marked on the marble inner lining. Bronze tablets, bricks and mortar were also employed in building the instruments in the monument spread over about 18,700 square metres. It was in continuous use until about 1800, then fell in disuse and disrepair. Restored again several times during the British colonial rule, particularly in 1902, the Jantar Mantar was declared a national monument in 1948. It was restored in 2006. The restoration process in early 20th century replaced some of the original materials of construction with different materials.
Jantar Mantar is managed under the Archeological Sites and Monuments Act of Rajasthan since 1961, and protected as a National Monument of Rajasthan since 1968