Our next goal is Jantar Mantar a medieval observatory built by Rajah Jai Singh II, who had a keen interest in mathematics, architecture and astronomy. It is one of five in India and the largest one and is also an Unesco World Heritage Site. Jantar Mantar actually means Calculation Instruments and that is what we have here over an extensive area, a collection of instruments helping with astronomical observations. For example Dakshin Bhitti Yantra, which looks like something of an Escherian dream measures the meridian, altitude and zenith distances of celestial bodies.
Unnatamsa Yantra, Yantra meaning instrument, would have been used to measure the altitude of celestial bodies. And so it goes with each instrument having each astronomical function which is quite difficult to guess at now today.
However the most impressive one is Vrihat Samrat Yantra which literally means the “great king of instruments”. It towers over all other instruments and is the world’s largest stone sundial. It is at least something that we can understand in principle how it would work.
We explore it for a while, marveling at the huge wall that is used as a needle and then tracing the shadow on the measuring tool. Given its height it was quite precise with an accuracy of about two seconds.
Given the more esoteric nature of the instruments here it is surprising how many people are visiting the site. There are guides and we listen in to a few of them but really they do not know more than the panels that we can read on our own.
Digambra Yantra is also interesting and would be valuable as a tool as it can predict the time of sunrise and sunset, quite useful for agriculture and possibly also warfare.
Rama Yantra, a complex tool, has a related function being used to measure the altitude and the azimuth of the Sun.
And then we explore a bit more including the gift shop and it is time to exit as we still want to visit the CIty Palace before it closes. Luckily it is very close so after exiting we are there in about five minutes for our last objective of the day.
