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Jantar Mantar

The Jantar Mantar is an 18th Century observatory built by Maharaja Jai Singh II.  This park was built in 1724 and was the first of five that Jai Singh built.  The others were at Jaipur, Ujjain, Varanai and Marthura, three of which are still in place.  The name comes from Yantra - meaning Instruments and Mantra meaning Formulae.  Jai Singh built these extra large instruments because he found the standard contemporary versions too small to take correct measurements.  The Maharaja actually designed some of the instruments himself.


This is the view of the instruments as you enter the park, there are four principle instruments here.  Some are missing some parts to make them work and some of the markings are worn away, also modern buildings obscure the sun at certain times.  Despite this it still makes a fascinating visit.



Andy is standing in front of the gnomon of the Samrat Yantra (Supreme Instrument).  Its hypotenuse lies parallel to the Earth's Axis.


















Samrat Yantra

This instrument measures the time of the day, in effect a super sized sundial.  It can also be used to find the declination of the sun and other heavenly bodies.   Just to the left of the photo above you can see part of one of the circle quadrants positioned either side of the gnomon from where readings can be taken.


Now both the quadrants can be seen.  The steps enable users to take the readings from the white marble planes that are engraved with the appropriate markings.

Despite the gate to the gnomon being locked, many people jumped over the gate to climb to the top.

















To learn more how this instrument works, use the following link.   www.khagolmandal.com/km_links/jantar_mantar/km_samrat_yantra.htm


Jai Prakash Yantra

This instrument also is used for finding the position of the sun and other planets, stars etc.  There should be a small disc suspended by a wire over the sun of the instrument, but that is no longer present.  While the sun gives a shadow of the disc during the day making readings straight forward and the moon may also at times provide enough light, other bodies have to be tracked by the user positioning themselves to sight the star through the disc.


The dial surface is made in the strips shown so that the user can stand on the steps to take their readings.  If the readings fall in the gaps then strips of wood could be used to extend the dials.













The following link shows some time lapse photography taken on a similar working instrument in Jaipur.


The route down into the instrument.














More instruments can be seen on the next page at JM2


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