Thread by @ancient_bharat

The Jantar Mantar is a collection of 19 architectural #astronomical instruments built by the Rajput king Sawai Jai Singh.
Which features many instruments along with the world's largest stone sundial
Vrihat Samrat yantra is sundial that can give local time to accuracy of 2 seconds

List Of Instruments:

Samrat Yantra - it measures time to a precision that had never before been achieved.

Jai Prakash Yantra - May well be Jai Singh’s most elaborate and complex instrument, See the time lapse video below to see how the Kappala Yantra tracks the sun’s movement.

Rama Yantra
consists of a pair of cylindrical structures,open to the sky, each with pole at the center.
The pillar & walls are of equal height,which is also equal to the radius of the structure. Those walls inscribed with scales indicating angles of altitude and azimuth.

In the early 18th century, Maharaja Jai Singh II of Jaipur constructed five Jantar Mantar in total, in New Delhi, Jaipur, Ujjain, Mathura and Varanasi; they were completed between 1724 and 1735.

The Jantar have like Samrat Yantra, Jai Prakash, Ram Yantra and Niyati Chakra;

Each of which are used to for various astronomical calculations. The primary purpose of the observatory was to compile astronomical tables and to predict the times and movements of the sun, moon and planets.

List Of Instruments:

Samrat Yantra
Jai Prakash Yantra
Disha Yantra
Rama Yantra
Chakra Yantra
Rashiwalay Yantra
Dingash Yantra
Utaansh Yantra

Description

Jantar Mantar deploys all three ancient coordinate systems of the five celestial coordinate systems known. In the image, the red (ecliptic) and blue (equatorial) coordinate systems are two of the three classical systems that feature in the monument's instruments

1. Chakra Yantra (4 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 4 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.)

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

3. 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)

4. Disha Yantra

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

6. 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)

7. 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)

8. Kanali Yantra

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

10. Laghu Samrat Yantra (the smaller sundial at the monument, inclined at 27 degrees, to measure time, less accurate than Vrihat Samrat Yantra)

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

12. 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)

13. Palbha Yantra

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

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

16. 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, Sun's pinhole image falls on a scale below enabling the observer to measure the zenith distance,declination,& the diameter of the Sun)

17. 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)

18. Vrihat Samrat Yantra (world's largest gnomon sundial, measures time in intervals of 2 seconds using shadow cast from the sunlight)

19. 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)

The instruments r in most cases huge structures.
The scale to which they have been built has been alleged to increase their accuracy
However,the penumbra of the sun can be as wide as 30 mm,making the 1mm increments of the Samrat Yantra sundial devoid of any practical significance

Additionally, the masons constructing the instruments had insufficient experience with construction of this scale, and subsidence of the foundations has subsequently misaligned them.

The samrat yantra, for instance, which is a sundial, can be used to tell the time to an accuracy of about two seconds in Jaipur local time.
The Giant Sundial, known as the Samrat Yantra (The Supreme Instrument) is one of the world's largest sundials, standing 27 metres tall.

Its shadow moves visibly at 1 mm per second, or roughly a hand's breadth (6 cm) every minute, which can be a profound experience to watch.

Maharaja Jai Singh II (3 November 1688 – 21 September 1743)
had a great interest in mathematics, architecture and astronomy. He commissioned the #JantarMantar observatories at multiple places in India, including his capital Jaipur.

Five observatories were built at
1. Delhi,
2. Mathura (in his Agra province),
3. Benares,
4. Ujjain (capital of his Malwa province),
5. and his own capital of Jaipur.

His astronomical observations were remarkably accurate.

Jai Singh's greatest achievement was the construction of Jaipur city (known originally as "Jainagara" (in Sanskrit, as the 'city of victory' & later as the 'pink city' by the British by the early 20th century),the planned city, later became the capital as the Indian state of Raj.

Built on the ancient Hindu grid pattern, found in the archaeological ruins of 3000 BCE, it was designed by Vidyadhar Bhattacharya who was educated in the ancient Sanskrit manuals (silpa-sutras) on city-planning and architecture.

Merchants from all over India settled down in the relative safety of this rich city, protected by thick walls, and a garrison of 17,000 supported by adequate artillery.

A Sanskrit epic by the name 'Ishvar Vilas Mahakavya' written by Kavikalanidhi Devarshi Shrikrishna Bhatt gives a good historical description of various important events of that era, including the construction of Jaipur city