Calculate time with World's Largest Sundial at Jantar Mantar Jaipur

Jaipur Jantar Mantar is located near City Palace and Hawa Mahal of Jaipur, the monument features masonry, stone and brass instruments that were built using astronomy and instrument design principles of ancient Hindu Sanskrit texts.

One of the highlights of the Jaipur Jantar Mantar are the dozen precisely angled structures that each target a specific constellation. Most of these were restored in 1901 and have been well-maintained up to the present day.

The name is derived from jantar (yantra, Sanskrit: यन्त्र, "instrument, machine"), and mantar (from mantrana, Sanskrit: मन्त्रण, "consult, calculate"). Therefore, Jantar Mantar literally means 'calculating instrument'. The instruments allow the observation of astronomical positions with the naked eye. The monument expresses architectural innovations, as well as the coming together of ideas from different religious and social beliefs in 18th-century India. The observatory is an example of the Ptolemaic positional astronomy which was shared by many civilizations.

The observatory consists of nineteen instruments for measuring time, predicting eclipses, tracking location of major stars as the earth orbits around the sun, ascertaining the declinations of planets, and determining the celestial altitudes and related ephemerides. The instruments are

• Chakra Yantra (four semicircular arcs on which a gnomon casts a shadow, thereby giving the declination of the Sun at four specified times of the day. This data corresponds to noon at four observatories around the world (Greenwich in UK, Zurich in Switzerland, Notke in Japan and Saitchen in the Pacific); this is equivalent of a wall of clocks registering local times in different parts of the world.)
• Dakshin Bhitti Yantra (measures meridian, altitude and zenith distances of celestial bodies)
• Digamsha Yantra (a pillar in the middle of two concentric outer circles, used to measure azimuth of the sun, and to calculate the time of sunrise and sunset forecasts)
• Disha Yantra
• Dhruva Darshak Pattika (observe and find the location of pole star with respect to other celestial bodies)
• Jai Prakash Yantra (two hemispherical bowl-based sundial with marked marble slabs that map inverted image of sky and allows the observer to move inside the instrument, measures altitudes, azimuths, hour angles and declinations)
• Kapali Yantra (measures coordinates of celestial bodies in azimuth and equatorial systems, any point in sky can be visually transformed from one coordinate system to another)
• Kanali Yantra
• Kranti Vritta Yantra (measures longitude and latitude of celestial bodies)
• Laghu Samrat Yantra (the smaller sundial at the monument, inclined at 27 degrees, to measure time, less accurate than Vrihat Samrat Yantra)[9]
• Misra Yantra
• Nadi Valaya Yantra (two sundials on different faces of the instrument, the two faces represent north and south hemispheres, the accuracy of the instrument in measuring the time is less than a minute)
• Palbha Yantra
• Rama Yantra (a double cylinder instrument that measures azimuth and altitudes of celestial bodies)
• Rashi Valaya Yantra (12 gnomon dials that measure ecliptic coordinates of stars, planets and all 12 constellation systems)
• Shastansh Yantra (next to Vrihat Samrat Yantra, this instrument is a 60 degree arc built in the meridian plane within a dark chamber. At noon, the sun's pinhole image falls on a scale below enabling the observer to measure the zenith distance, declination, and the diameter of the Sun.)
• Unnatasha Yantra (a metal ring divided into four segments by horizontal and vertical lines, with a hole in the middle; the position and orientation of the instrument allows measurement of the altitude of celestial bodies)
• Vrihat Samrat Yantra (world's largest gnomon sundial, measures time in intervals of 2 seconds using shadow cast from the sunlight)
• Yantra Raj Yantra (a 2.43-metre bronze astrolabe, one of the largest in the world, used only once a year, calculates the Hindu calendar)

Vrihat Samrat Yantra, The Supreme Instrument

The most imposing of the Jaipur Jantar Mantar’s astronomical structures is the giant sundial known as the Samrat Yantra (The Supreme Instrument). A staircase rises 27 meters (88.5 ft) to a small cupola where notable readings were announced. With instruments of this type, size does matter: the Samrat Yantra is the world’s largest sundial and can tell the time with an accuracy of 2 seconds.

The measuring surfaces of the Samrat Yantra and other calculating instruments are faced with white marble and have incised notches used to note the path of the sun’s shadow. Observers can actually view the progress of the shadow, which moves at a rate of 1 mm 1/25 of an inch) per second, or 6 cm (2.4 inches) per minute.

Laghu Samrat Yantra

The small Sun dial or Laghu Samrat Yantra is the instrument used for time calculation. From one side wall is inclined at an angle of 27 which is equivalent to latitude of Jaipur. It is graduated to the scale of tangent, to find out the declination angle of the sun.

On each side of gnomon, there are two quadrants. The left for time in the morning and right for afternoon. Both the quadrants are divided by 6 hrs, 60 min. and each minute by 60 seconds. With the help of the shadow of the gnomon which falls on one of the quadrants, we find out the time of Jaipur.

You can watch the working of Samrat Yantra in this VIDEO by IndiaVideo.org

The unique impression of the Jantar Mantar results from the combination of modern mathematical precision with the rich patina of time. As such, the captivating angles and curves of the instruments appeal greatly to painters and photographers.

 The Jantar Mantar is relatively unknown as ancient monumental works go, as are the significant accomplishments of India’s medieval astronomers. It is hoped that the preceding exploration will help change that… though only time will tell.