It's probably impossible to understand the science behind the instruments if you aren't an Astrophile or an Astronomer. Audio tour doesn't really work. It's incomprehensible to grasp the intricacies of astronomy through audio tour. I had tried the audio tour at City Palace, so instantaneously discarded the idea of audio tour. We hired a guide in a hope to understand at-least the basic idea behind the concept to make our visit to Jantar Mantar an accomplishment.
Maharaja Sawai Jai Singh (Jai Singh II) took over the rule of Amber at just the age of 11. He was attracted towards astronomy from an early age and would study works of celebrated astronomers of those times. I've read somewhere that Jai Singh apparently followed the astronomer, Ulugh Beg.
He first built an observatory with instruments of ashlar (stonework) in Delhi and later on he built observatories at Jaipur, Ujjain, Varanasi and Mathura. The observatory in Mathura is almost obsolete.
Jantar Mantar literally translates into "instruments for measuring the harmony of the heavens". The one in Jaipur is the biggest and well-preserved among all the five Jantar Mantar across India. It's added to UNESCO World Heritage site in 2010. It holds almost all of the King's instruments with a higher degree of precision. The astronomical instruments are so precise and abiding that they are still used today for astronomical observations and calculations.
The place has some kind of hypnagogic and abstract charm. I was standing in awe ringed by enormous yet classic structures. It feels like a mystical and esoteric world. The instruments were created with utter mathematical precision for mapping out the movements of the sun, moon and stars specifically in Jaipur's sky.
These instruments are known as yantras which is a Sanskrit word for instrument. The “Rashivalaya Yantra” makes Jantar Mantar, Jaipur unique and one-of-a-kind.
He built Jantar Mantar near to his palace (City Palace) so that he could himself do the astronomical observations at the observatory.
Sawai Jai Singh dawned as the philanthropist of astronomy of his aeon in India. His works on reform of the Calendar and prediction of eclipses were phenomenal. A set of astronomical tables made by the Raja was named as the “Zeech-i-Muhammad Shahi” in honor of then Mughal Emperor Mohammad Shah.
It was impressive to notice the knowledge of our guide about astronomy. He found out my moon and sun signs with utter ease using Rashi Valaya Yantra. He tried to make us understand the time calculations using sun-dial. Hubby understood the concept while I was still scratching my head; guide on perceiving the situation smiled telling not to try too hard to understand as after spending 25 years even he doesn't know many things. Though I was happy to know the history behind the concept. I didn't understand the exact working of the instruments but it was insightful enough to realise that Sawai Jai Singh was a genius.
Let's have a brief look at the instruments created by Sawai Jai Singh in Jaipur observatory.
1. Laghu Samrat Yantra (small sun-dial): The sun-dial is according to the Jaipur latitude 27 degrees north. To match it with IST, anything from 1 minute to 38 minutes must be added to the time shown by the shadow on sun-dial.
2. Vrihat Samrat Yantra (large sun-dial): It's a huge sundial which operates on the same assumptions as its smaller twin, but because of its bigger size it shows accurate time. As told Raja wasn't happy with the small sundial so he built ten times bigger than the earlier with greater accuracy. It is accurate to 2 seconds as compare to 20 seconds of small sun-dial.
3. Shasthansh Yantra (sextant instrument): The variation in the sun's diameter can be accurately measured, and even sun spots could easily be observed.
4. Dhruvdarshak Pattika (pole star viewing plate): It's used for finding the position of the Pole Star at night and also shows the position of the twelve zodiac signs and measures the declination of the sun.
5. Krantivritta Yantra (the ecliptic circle instrument): An astrolabe used for the direct measurement of the longitude and latitude of the celestial bodies.
6. Yantra Raj (the astrolabe): It's called the king of instruments. It's a map of the visible parts of the celestial sphere, which can be used to compute a huge amount of astronomical data.
7. Unnantansh Yantra (altitude instrument): A brass circle used for detecting the altitudes of celestial bodies.
8. DakshiNottar Bhatti Yantra (meridian wall instrument): It's used for noting the position and movement of heavenly bodies when passing over the meridian.
9. Rashivalaya Yantra (zodiac sign instrument): There are twelve sundials, one for each zodiac sign. One can easily find his or her own sign. Each instrument works in absolutely the same way as the samrat yantras.
10. Nadivalaya Yantra (equatorial instrument): A sundial with two ashlar dials, one facing south and the other north. The former is used when the sun is in the Southern Hemisphere and the latter when the sun is in the Northern Hemisphere.
11. Jai Prakash Yantra: This is the Master instrument constructed by Maharaja Sawai Jai Singh himself and is the magnum opus of the Jaipur Observatory. It verifies all the other instruments and is quite unique to the Jantar Mantar, Jaipur. It measures the rotation of the sun. It consists of two hemispherical cavities set in the ground. They are interdependent i.e. if put together they would form one complete hemisphere, which would be a map of the heavens.
12. Kapali Yantra (hemispherical bowl instrument): It is a miniature version of the Jai Prakash. Raja wasn't satisfied with Kapali Yantra because there was no way to get inside as no pathways were cut inside the bowl.
13. Ram Yantra (altitude instrument): The Ram Yantra performs with an upright building what the Jai Prakash performs with a sunken hemisphere. It is used to find the altitude and the azimuth of the sun. There is also a small ram yantra, which is basically a working model of the larger one.
14. Palbha Yantra (horizontal sun-dial)
15. Chakra Yantra (circle instrument): It is a doppelganger to the modern instrument known as an equatorial. This brass circle is rotated about a diameter parallel to the earth's axis, this gives the rise and decline i.e. angle of an object from the equator.
16. Digansha Yantra (azimuth instrument): It measures the azimuth, that is, the angle of any celestial body with the horizon.
Jantar Mantar definitely stands tall witnessing the scientific expertise of our nation since ages that enhances our country's culture and heritage all across the world.