Jai Prakash Yantra

Jantar means "instrument" and Mantar is usually translated to "formula". "Jantar Mantar is loosely translated as "instrument for calculation".

One of Maharaja Sawai Jai Singh's interest was in astronomy. He kept his scientific interest alive by building solar observatories. The king has built five observatories, respectively in Delhi, Ujjain, Mathura, Varanasi and of course, Jaipur. Only the one in Jaipur is still operational, preserved since the first half of the 18th centure. That - was the one we went to.

The photo above is Jai Prakash Yantra. It comprises of two sunken hemispheres, mapping out the heavens. They are used to locate the position of stars based on two different coordinates measurements systems, the horizontal and celestial equatorial systems. This was believed to be invented by Jai Singh himself to verify the accuracy of other instrument in the observatory.

Ram Yantra

Next to Jai Prakash Yantra, one will find some vertical columns. The vertical columns support an equal number of horizontal slabs in two identical stone structures in this instrument. This structure is named Ram Yantra. They are used in complementary to each other. In the centre of each, there is a perpendicular rod of the same height as the stone structure. One can also see twelve stone triangles fixed to the ground. These stone slabs are divided up from 90 degree to 45 degrees. The circular wall is marked off from 45 to 0 degree. This is used in calculating the movement of the stars.

Samrat Yantra

Samrat Yantra, the largest instrument in Jantar Mantar, this sundial stood 27 meters high and could be used to tell time, both day and night with an accuracy of about two seconds. The difference of this sundial compared to the other sundials is the the stick (termed gnomon) that creates a shadow and a flat scale on which time is read. Samrat Yantra's gnomon is a huge triangle made of stone.

This sundial also used to forecats the ccrop prospects for the year. In this same observatory, Samrat Yantra has a small "little brother" - a smaller version of sundial named Laghu Samrat Yantra. This is used to calculate Jaipur's local time up to an accuracy of 20 seconds.

We had our guide with us at this location as well, and he was a strict guide, always giving us a time limit to 'regroup'. = ="


Side note: Have you heard of the 5:2 diet?