In the grounds of the royal palace at Jaipur, capital of the Indian state of Rajasthan, tourist today wonder through what looks like the abandoned stage set of some science fiction spectacular – a scattering of impressive stone structure in strange and varied geometrical shapes. The uninformed visitor could hardly guess that these monuments are precision astronomical instruments for the study of the sun, moon, stars.

Jantar Mantar Overview picture

For Hindus , as for many years religions, the calendar of religious ceremonies and festival depends upon a knowledge of astronomy. Many worshippers visits the holy sites of the Ganges whenever there is an eclipse of the sun, for example, and therefore want to know when an eclipse is eminent. In the early 18^th century an Indian prince the maharaja sawai Jai Sing, was worried that accurate astronomical observation was not made.

Jai Singh set out to revive Hindu astronomy and the perfect the calendar and the official tables showing the movements of the heavenly bodies. A total of five observatories were build to Jai Singh instructions the most important were at Delhi, Jaipur, and Ujjain.

The instruments are in most cases huge structures. They are built on a large scale so that accuracy of readings can be obtained. An excursion through Jai Singh’s Jantar is the singular one of walking through solid geometry and encountering a collective weapons system designed to probe the heavens. Amongst all the instruments, the Sundial usually attracts the maximum attention of people, which tells the time to an accuracy of about two seconds in local time of Jaipur of Rajasthan.

It is considered the largest sundial in the world.  Jantar Mantar was carefully renovated in 1901 and was declared a national monument in 1948. Today the main purpose of the observatory is to function as a tourist attraction.

Inside

At Jaipur the monumental structures include the largest sundial in the world with the gnomon (the projecting arm that cast the shadow) On at least one occasion Jai Sing was able to improve on observation of the moon and planets made by his contemporaries in western Europe, with whose work he was well acquainted.

Ujjain is still know to orthodox Hindus as the as the “Greenwich of India” and Jai Singh himself is remembered as the “Newton of the Orient”.

Ram Yantra of Jantar Mantar in Rajasthan

It is an instrument used to indicate the altitude and the azimuth or declination of celestial bodies.

Jai Prakash Yantra of Jantar Mantar in Rajasthan
It is used to find out the positions of the celestial bodies during days and nights. It is a two hemispherical bowl structure, which represents the celestial sphere and there is a vertical rod in the center.

Dhruva Yantra of Jantar Mantar in Rajasthan
The Dhruva Yantra is used to locate the position of 12 Zodiac signs and also the Pole Star at night. The traditional unit of measurement started with the smallest unit being ‘human breath’ that has been calculated to be of 6 seconds duration. According to this scale, 4 breaths or 24 seconds equals 1 pal, 60 pals or 24 minutes equals 1 ghadi and 60 ghadis or 24 hours equals 1 day.

Narivalya Yantra of Jantar Mantar in Rajasthan
The Narivalya Yantra is a distinctive sundial with two dials – the first dial facing south reads time when the sun is in the southern hemisphere, i.e., from 21 September to 21 March and the other one facing north reads time for the rest of the year when the sun is in the northern hemisphere, i.e., from 21 March to 21 September.

Kranti Yantra of Jantar Mantar in Rajasthan

Kranti Yantra is used for direct measurement of the longitude and latitude of the extraterrestrial bodies.

Raj Yantra of Jantar Mantar in Rajasthan
Raj Yantra or the King of Instruments was used only once a year to calculate the Hindu calendar.

Unnsyhsmsa Yantra of Jantar Mantar in Rajasthan
Unnsyhsmsa yantra was used for finding the altitudes of the heavenly bodies.

Chakra Yantra of Jantar Mantar in Rajasthan
The Chakra yantra gives the angle of an object from the equator.

Disha Yantra of Jantar Mantar in Rajasthan
Disha yantra or the compass always points to the north.

Dakshina Yantra of Jantar Mantar in Rajasthan
Dakshina yantra was used for observing the position and movement of heavenly bodies when passing over the meridian.

Large Samrat Yantra of Jantar Mantar in Rajasthan
The Large Samrat Yantra is ten times larger than the Samrat Yanta and ten times more accurate too. It is accurate down to 2 seconds and is also used to predict the length and heaviness of the monsoon for the local area.

Rashivalayas Yantra of Jantar Mantar in Rajasthan
The Rashivalayas Yantra has 12 sundials for the signs of the zodiac while Jai Prakash Yantra acts as a double check on all the other instruments.