UNESCO’s World Heritage Site

Jaipur’s Jantar Mantar is a collection of 19 astrological instruments established by Rajput king Sawai Jai Singh II, the city’s founder. In 1734, the monument was completed. It is a UNESCO World Heritage site with the world’s largest stone sundial. It’s close to the City Palace and the Hawa Mahal. The instruments enable for naked-eye observation of astronomical positions. The observatory is an example of Ptolemaic positional astronomy, which was widely used.

The horizon-zenith local system, the equatorial system, and the ecliptic system are all represented by instruments on display at the monument.

The Kanmala Yantraprakara is a two-system device that allows direct coordinate transformation from one system to the other. It has the world’s largest sundial.

In the nineteenth century, the monument was damaged. During Major Arthur Garrett’s appointment as Assistant State Engineer for the Jaipur District, early restoration work was overseen by a keen amateur astronomer.

History

It is unknown when Raja Jai Singh began construction in Jaipur, but by 1728, several instruments had been completed, and development continued in Jaipur until 1738. At least 23 astronomers were employed at Jaipur in 1735, when building was at its pinnacle, and due to the changing political climate, Jaipur displaced Delhi as Raja Jai Singh’s main observatory, and remained Jai Singh’s major observatory until his death in 1743. Because of a succession conflict between Isvari Singh (r.1743-1750) and his brother, the observatory lost support. Isvari Singh’s successor, Mado Singh (r. 1750–1768), sponsored the observatory, albeit it did not see the same degree of activity as Jai Singh’s. Despite minor improvements to the Jantar Mantar during Pratap Singh (r.1778-1803), the observatory’s activity dwindled. A temple was built at this time, and Pratap Singh repurposed the observatory site into a weapons factory.

In 1876, Ram Singh (r. 1835–1880) finished the restoration of the Jantar Mantar, making some of the instruments more durable by injecting lead into their lines and repairing some of the plaster instruments with stone. The observatory, however, was soon neglected again, and it was not restored until 1901, under the reign of Madho Singh II (r. 1880–1922).

Description

The observatory has nineteen instruments that measure time, predict eclipses, follow the location of significant stars as the earth circles around the sun, determine planet declinations, and calculate celestial altitudes and related ephemerides. The following instruments are listed alphabetically:

• Chakra Yantra (four semicircular arcs on which a gnomon casts a shadow, revealing the Sun’s declination at four different times of day. This data is analogous to a wall of clocks registering local times in several areas of the world (Greenwich in the United Kingdom, Zurich in Switzerland, Notke in Japan, and Saitchen[clarification needed] in the Pacific).

• Yantra of Dakshin Bhitti (measures meridian, altitude and zenith distances of celestial bodies)

• Yantra Digamsha (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)

• Yantra of Disha (used to detect the direction)

• Pattika Dhruva Darshak (observe and find the location of pole star with respect to other celestial bodies)

• Yantra of Jai Prakash (two hemispherical bowl-based sundials with marked marble slabs that map inverted images of sky and allow the observer to move inside the instrument; measures altitudes, azimuths, hour angles, and declinations)

• Yantra of Kapali (measures coordinates of celestial bodies in azimuth and equatorial systems; any point in sky can be visually transformed from one coordinate system to another)

• Yantra of Kanali

• Yantra Kranti Vritta (measures longitude and latitude of celestial bodies)

• Yantra of Laghu Samrat (the smaller sundial at the monument, inclined at 27 degrees, to measure time, albeit less accurately than Vrihat Samrat Yantra)

• Misra Yantra (meaning mixed instrument, it is a compilation of five different instruments)

• Nadi Valaya Yantra (two sundials on different faces of the instrument, the two faces representing north and south hemispheres; measuring the time to an accuracy of less than a minute)

• Palbha Yantra

• Rama Yantra (an upright building used to find the altitude and the azimuth of the sun)

• Rashi Valaya Yantra (12 gnomon dials that measure ecliptic coordinates of stars, planets and all 12 constellation systems)

• The Shastanadan Yantra (next to Vrihat Samrat Yantra) Within a pitch black room is a meridian plane arc of sixty degrees that is integrated into this device. During the middle of the day, the pinhole image of the sun will fall on a scale that will allow the observer to determine the zenith distance, the declination, and the diameter of the sun.  Unnatamsa 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)

Theory

The Vedas describe astronomical words, time measurement, and calendars, but no astronomical tools are mentioned. The Vedangas, ancient Sanskrit scriptures, contain the earliest mention of astronomical equipment such as the gnomon and clepsydra. Many subsequent literature, such as the Katyayana Sulbasutras, discuss the gnomon (named Shanku) located at the Jantar Mantar monument. Other Hindu scriptures, like the fourth-century BCE Arthashastra, Buddhist texts like Sardulakarna-avadana, and Jain texts like Surya-prajnapti, mention astronomical equipment. The theories underpinning the instruments can be found in books by Aryabhatta in the fifth century CE, Brahmagupta and Varahamihira in the sixth century CE, Lalla in the ninth century, Sripati in the eleventh century, and Bhaskara in the eleventh century. Bhaskara’s works have devoted chapters on instruments, which he refers to as Yantra-adhyaya.

In ancient writings, the theories of chakra-yantra, yasti-yantra, dhanur-yantra, kapala-yantra, narivalaya-yantra, kartari-yantra, and others may be found.

Conclusion 

Jaipur’s founder, Rajput king Sawai Jai Singh II, built the 19-instrument Jantar Mantar. Completed in 1734. UNESCO World Heritage site with largest stone sundial. City Palace and Hawa Mahal are nearby. Instruments allow naked-eye astronomical observation. The observatory used Ptolemaic positional astronomy.The monument’s instruments symbolise the horizon-zenith, equatorial, and ecliptic systems.The Kamala Yantraprakara converts coordinates directly between two systems. World’s largest sundial.

Damaged in the 19th century. An amateur astronomer oversaw early repair work when Major Arthur Garrett was Assistant State Engineer for the Jaipur District.