- Yantra Mandir
The Yantra Mandir (commonly known as the Jantar Mantar) is an equinoctial dial, consisting a gigantic triangular
gnomon with thehypotenuse parallel to theEarth 's axis. On either side of the gnomon is a quadrant of a circle, parallel to the plane of theequator . The instrument is intended to measure the time of day, correct to half a second,Fact|date=December 2007 anddeclination of theSun and the otherheavenly bodies .In the early
18th century ,Maharaja Jai Singh II ofJaipur constructed five Yantra Mandirs in total, inDelhi ,Jaipur ,Ujjain ,Mathura andVaranasi ; and were completed between 1724 and 1735. The most famous Yantra Mandirs are:*
Jantar Mantar, Jaipur
*Jantar Mantar, Delhi 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 andplanets . [http://sankalpindia.net/drupal/?q=jantart-mantar-get-lost-space]External links
* [http://www.jantarmantar.org/ Jantar Mantar - The Astronomical Observatories of Jai Singh II]
* [http://perso.orange.fr/cadrans.solaires/cadrans/cadrans-jaipur.html pictures with french text]
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