Thursday, January 29, 2015

reach out

Thought behind the Thought

I am an avid sky watcher. Ever since I was a little child, I have been fascinated with the sky, the stars, and what lies beyond. Figuring out the patterns in the sky and trying to link it up in stories that I have read, imagining the celestial bodies moving about with their own forces and intentions is still a source of wonderment and joy to me.

And so it must have been, with our ancestors who gazed up at the skies. Almost all civilisations in the world developed their own astronomical theories and beliefs and tried to make sense of the world around, and of our position in the scheme of things.

And to finally reach out to the stars, both literally and figuratively!

Art, Design, Architecture

The 'Jantar Mantar', one of the most fascinating demonstrations of Indian astronomical study and construction, is a complex of built 'instruments' that measure heavenly phenomenon. Maharaja Jai Singh II of Jaipur, a patron of science and arts, constructed five such astronomical observatories between 1727 and 1834. Situated at Delhi, Ujjain, Varanasi, Mathura and Jaipur, these observatories are also fascinating visual art ... a striking combination of geometrical forms at large scale.
The grandest of these is the Jantar Mantar at Jaipur, and also the best preserved. Built in stone, a material that is perhaps as immortal as the science itself, the instruments are very accurately designed and crafted. Marble is used where the surfaces are clearly visible and great accuracy is also required. The observatory is still in use for both calculation and teaching purposes and still retains it's precision and accuracy. The various instruments are called 'Yantras' (Sanskrit word for instrument or machine)

Small Samrat Yantra
This is a sundial. It consists of a right-angled triangle, the hypotenuse of which is parallel to the earth's axis and which casts a shadow on one of the two quadrants below it. Each edge of the quadrants is marked in hours, minutes, and degrees. It gives the time to an accuracy of twenty seconds.

Large Samrat Yantra
An enormous sundial that towers majestically over the observatory. It operates on the same principles as its smaller counterpart, but it is ten times bigger and thus accurate to two, rather than twenty seconds. 

Dhruva Yantra
A brass instrument for finding the position of the Pole Star at night, it also serves to show the position of the twelve zodiac signs, each comprising 30 degrees of the celestial circle, and measures the declination of the sun 

Narivalya Yantra
A sundial with two masonry dials, one facing south and the other north. The former is used when the sun is in the Southern Hemisphere, from September 21 to March 21, and the latter when the sun is in the Northern Hemisphere, from March 21 to September 21. The central iron pinpoints to the pole. At noon the sun falls on the north-south line; before noon the shadow will lie to the west, and after noon to the east. The time is read in the normal way.

Large and Small Kranti Yantra
An astrolabe made of masonry and brass. One of the circles rotates in the plane of the equator, the other in the plane of ecliptic. It is used for the direct measurement of the longitude and latitude of the celestial bodies, and it can be used day or night.

Raj Yantra
"The king of instruments," this astrolabe is a map of the visible portions of the celestial sphere, which can be used to calculate a vast amount of astronomical data. A telescope is fixed to a rod that passes through the central hole. The back of the yantra is fitted with a bar used for sighting. The plain disk to the left is intended for use as a blackboard, to record observations and calculations as they are made.

Unnathamsa Yantra
A huge graduated brass circle used for finding the altitudes of celestial bodies. The circle can be revolved so that observations can be made at any time, day or night, and the sunken steps allow any part of the circle to be read.

Dakshina Yantra
A wall built aligned along the north-south meridian. The inscribed arcs on either face of the wall are made of marble and marked in degrees and minutes. It was used for observing the position and movement of heavenly bodies when passing over the meridian (an imaginary circle linking the poles that the sun crosses at midday).

Rashivalayas Yantra
Twelve sundials, one for each sign of the zodiac. Each instrument works in exactly the same way as the samrat yantras. The instruments have been so constructed that one is available at the instant each zodiacal sign crosses the meridian; hence they enable observations to be made approximately every two hours.

Jai Prakash Yantra
This elegant instrument acts as a double check on all the other instruments and is unique to the Jantar Mantar. The Jai Prakash measures the "rotation" of the sun. It consists of two hemispherical cavities set in the ground. They are complementary; if put together they would form one complete hemisphere, which would be a map of the heavens.
There is an underground passage connecting the two bowls. This is a fine example of Jai Singh's love of things that were both practical and aesthetically pleasing.

Large Ram Yantra
This and its smaller version have the same function. What the Jai Prakash does with a sunken hemisphere, the Ram Yantra does with an upright building. These two structures fit together to make one whole instrument. A sector in one building corresponds to a space in the other. The yantra is used to find the altitude and the azimuth of the sun. 

Chakra Yantra
A graduated brass circle that can be revolved about a diameter parallel to the earth's axis, this gives the ascension and declination – that is, angle of an object from the equator. 

Diganta Yantra
A simple and useful instrument to measure the azimuth, that is, the angle of any celestial body with the horizon. 


  1. This comment has been removed by the author.

  2. Jantar mantar ..I am amazed by maharajah jaisingh's quest for knowledge in this field.. Thanks to him we have the awesome experience of seeing the jantar mantar yantras. The sun dial clock has always fascinated me ever since the first time I saw it and saw how accurately it cab tell the time.

  3. Jantar Mantar is just so amazing. Hats off to our ancestors

  4. Another scientific marvel of our ancestors...