Jantra-Mantra : An Astronomical Heritage of India.
Jantra-Mantra : An Astronomical Heritage of India.
Introduction
Jantra Mantra
commanly know as jantar-mantar. Jantra means yantras or instruments and
mantra means formulas.
Jantar Mantar is an astronomical observatory and equinoctial sundial that dates to the 18th century. A visit to this place will help you explore old-word astronomy and understand how people of bygone eras determined the time and discovered the location and movements of celestial bodies.
Fig:
Jantar mantar, Delhi
It consists of
13 architectural astronomy instruments, built by Maharaja Jai Singh II of
Jaipur, from 1724 onwards. as he was given by Mughal emperor Muhammad Shah the
task of revising the calendar and astronomical tables. In fact, the king had
established five observatories during his reign in the early 18th century and
the one in Delhi was the first to be built among these five.
The other four
observatories are in Jaipur, Varanasi, Ujjain, and Mathura.
The primary
purpose of the observatory was to compile astronomical tables, and to predict
the times and movements of the sun, moon and planets. Some of these purposes
nowadays would be classified as astronomy.
King Sawai Jai Singh II
Jai Singh was
born in 1688 at Amber in the region of Rajasthan that is now Jaipur. He
ascended the throne when he was 12 years old, following the death of his
father, Bishan Singh. The young king was bright, eager to learn, and socially
and politically astute. Among his many later accomplishments, he founded the
city of Jaipur which bears his name and was responsible for much of its design.
One must
appreciate the culture in which Jai Singh lived. It is a culture that
throughout its history has embraced the richness of sensory experience in its
arts and sciences - exemplified in the precise and complex forms that developed
in art, architecture, and music. Observation of natural phenomena, including
the apparent movement of stars and planets became a part of the Hindu’s world
view, and informed a myriad of life processes from agricultural practices to
religious rituals, to personal decisions of when and who to marry.
By the 14th
century, Indian astronomers had perfected the instrument and were producing
individual models with fine craftsmanship and beautiful ornamentation. Jai
Singh would have received his early instruction in astronomy using the
astrolabe, and in fact one of the early instruments at his observatory in
Jaipur is the Yantraraja, a great Astrolabe approximately 8 feet in height.
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Despite the
importance of the astrolabe in astronomical calculations, Jai Singh noted that
the tables that had been created earlier were often not in agreement with
current observations. His own research suggested that the brass instruments
that had been used to establish the earlier tables may have lost accuracy due
to the wear of their moving parts. It was in part, in reaction to this problem,
and through his own studies of geometric models, that Jai Singh conceived of an
observatory with the stability and permanence of masonry, and the capacity for
accuracy arising from large scale.
Modern scholars
of Jai Singh and his astronomy suggest there may have been other factors that
motivated him. In the political turbulence of his times, it may have suited
both his need to maintain good standing with the seat of power in Delhi, and
his need to maintain authority in his own region, to erect these monumental
structures.
Jantar Mantar
Architecture
The huge
observatory contains several astronomical structures and instruments, all of
which are built entirely of masonry. These instruments were built using brick,
limestone, and rubble, and finally plastered. Another unique feature of Jantar
Mantar, Delhi is that it is an outdoor observatory. All the instruments here
are installed in the open rather than being enclosed within buildings or rooms.
Though the
structures and instruments have stood the test of time, they did need a bit of
repairing and restoring over the years.
Influence
Jantar Mantar
sculptural structures inspired contemporary art and architecture. In 2008
Tatiana Bilbao designed the Observatory House in collaboration with the artist
Gabriel Orozco, who visited Jantar Mantar astronomical observatory in 1996.
Structures inside the Jantar Mantar
Complex
The Jantar Mantar
observatory in Delhi comprises of 13 astronomical instruments of which four are
primary devices. These are Samrat Yantra, the Jayaprakash Yantra, the Rama
Yantra, and the Misra Yantra. Most of these instruments were designed by
Maharaja Jai Singh II.
The Instruments
Samrat Yantra
Also known as
the Supreme Instrument, it stands as the main structure inside the observatory.
This structure is 70 feet in height, 114 feet in length at the base, and 10
feet thick. It is a giant triangle-shaped sundial with a hypotenuse that is 128
feet in length. This hypotenuse is placed parallel to the axis of the Earth and
is pointed towards the North Pole. On either side of the triangle, a quadrant
exists which has graduations that indicate the seconds, minutes, and hours.
The Samrat
Yantra, sometimes called “Supreme Instrument” is an equinoctial sundial of
enormous proportion.
Although one of
the simpler instruments, and not too different from sundials which had been
developed hundreds of years earlier, the Samrat Yantra is important because it
measures time to a precision that had never been achieved.
The Samrat
Yantra at Jaipur, for example, is capable of measuring time to an accuracy of
two seconds.
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How it works?
The essential
parts of the Samrat Yantra are the gnomon, a triangular wall with its
hypotenuse parallel to earth’s axis, and a pair of quadrants on either side,
lying parallel to the plane of the equator. On a clear day, as the sun passes
from east to west, the shadow of the gnomon falls on the scale of the quadrant,
indicating local time. Since a sundial gives the exact time for its locality
only, a formula to obtain standard time is used that compensates for the
longitude difference between the instrument location and its time zone, and the
daily adjustment that must be made due to the earth’s orbit around the sun.
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Jayaprakash Yantra
The Jayaprakash
consists of hollowed out hemispheres with markings on their concave surfaces.
Crosswires were stretched between points on their rim. "Jai Prakash Yantra
consists of two concave hemispherical structures used for ascertaining the
position of the sun and other heavenly bodies. This instrument is an efficient
dial, showing at any instant the local time, the sun's declination, and the
sign of the zodiac." written on the plaque on the site.
The Jai Prakash
may well be Jai Singh’s most elaborate and complex instrument. It is based on
concepts dating to as early as 300 B.C. when the Greco-Babylonian astronomer
Berosus is said to have made a hemispherical sundial.
Hemispherical
dials also appear in European Church architecture during the Middle Ages, and
at the observatory in Nanking, China in the late 13th-century. The Jai Prakash,
however, is much more elaborate, complex, and versatile than any of its
predecessors.
How it Works
The Jai Prakash
is a bowl-shaped instrument, built partly above and partly below ground level,
as can be seen in the drawing below. The diameter at the rim of the bowl is
17.5 feet for the Jaipur instrument, and 27 feet at Delhi. The interior surface
is divided into segments, and recessed steps between the segments provide
access for the observers. A taut crosswire, suspended at the level of the rim,
holds a metal plate with circular opening directly over the center of the bowl.
This plate serves as a sighting device for night observations and casts an
easily identifiable shadow on the interior surface of the bowl for solar
observation. The surfaces of the Jai Prakash are engraved with markings
corresponding to an inverted view of both the azimuth-altitude, or horizon, and
equatorial coordinate systems used to describe the position of celestial
objects.
Fig : (Left) Plan of Jayaprakash Yantra and
(Right) 3-D figure of Jayaprakash Yantra
Rama Yantra
This instrument
has two large structures of cylindrical shapes with open tops. Both these two
buildings form a complete device. These structures help to determine the
altitude of the stars based on the longitude and latitude of the Earth. The
pillar/post and walls are of equal height, which is also equal to the radius of
the structure. The floor and interior surface of the walls are inscribed with
scales indicating angles of altitude and azimuth. Rama Yantra was constructed
at the Jaipur and Delhi observatories only.
Working
The Rama Yantra
is used to observe the position of any celestial object by aligning an object
in the sky with both the top of the central pillar, and the point on the floor
or wall that completes the alignment. In the daytime, the sun’s position is
directly observed at the point where the shadow of the top of the pillar falls
on the floor or wall. At night, an observer aligns the star or planet with the
top of the pillar and interpolates the point on floor or wall that completes
the alignment using a sighting guide.
The floor is
constructed as a raised platform at chest height and is arranged in multiple
sectors with open spaces between them. This provides a space for the observer
to move about and comfortably sight upwards from the inscribed surface. The
instrument is most accurate near the intersection of floor and wall,
corresponding to an altitude of 45 degrees. Here, the markings are at their
widest spacing, and give an accuracy of +/- 1’ of arc. For altitude readings
greater than 45 degrees, the accuracy diminishes, and diminishes to +/- 1
degree near the base of the pillar.
Misra Yantras
It consists of five
different instruments which are used to find out the longest and the
shortest days of the year. These instruments are known as the Dakshinottara
Bhitti, Samrat, Niyat Chakra, Karka Rasivalaya, and the Western Quadrant. The
Misra Yantra is also effective for determining the exact noon time. It is
believed to be the only instrument in the Jantar Mantar that was not invented
by Maharaja Jai Singh II.
The Mishra
yantras were able to indicate when it was noon in various cities all over the
world.
Digmasa yantra
The Digamsa
(Azimuth) Yantra, used for measuring the Azimuth of any celestial object. The
design and function system of the Digamsa Yantra was relatively less complex
than the Jai Prakash and Rama Yantras. The only purpose it was built was to
provide accurate azimuthal readings to complement the Rama Yantra.
A Digamsa
yantra, consisting of two cylindrical walls surrounding a central pillar,
measures the angle of azimuth of a celestial body. Its central pillar as well
as its walls are engraved in degrees and minutes at their top surfaces. Cross
wires are stretched between the cardinal points marked over the outer wall. The
observer uses one or more strings with one end tied to a knob on the pillar and
the other end to stone pebbles suspended over the walls. With these strings,
the observer defines a vertical plane containing the crosswire and the object
in the sky. The angular distance of the vertical plane from the north point,
read on the scales, indicates the azimuth of the body. It was developed by Jai
Singh independently. Built only at Jaipur, Varanasi, and Ujjain.
Nadivalaya Yantra
Nadivalaya is an
equinoctial sundial more analogous to the European sundials. It has two
circular dials in the plane of the Equator - a North facing one and a South
facing one.
Construction of
the instrument:
Unlike usual
sundials fall when Nadi Valaya Yantra (Yantra Nadivalaya Gola) - following -
the following characteristics in mind: There is a double sundial - the small
building has on both the front and on the back of a sundial. Only the northern
disc dates from the time of Jai Singh, the southern slice of red sandstone and
white marble was replaced by his grandson Maharaja Pratab Singh. The dial is Nadivalaya
northern Uttar Gola, southern dial bears the name Nadivalaya Dakshin Gola. Both
are exactly parallel to each other.
The faces of the
dials are highly inclined. You are exactly perpendicular to the ramp of the
neighboring Laghu Samrat Yantra. Critical to the operation is the integration
of the geometry of the Clock in the geometry of the Earth:
The rod-shaped
hands of both discs is exactly parallel to the ramp of the neighboring Laghu
Samrat Yantra and shows exactly on the celestial north or south pole.
It is normal to
the dials The dials are so inclined to be parallel to the ground and thus to
the celestial equator are. This means that the disks are tilted by 27 ° from
the vertical, ie exactly at the latitude of Jaipur. For such a width that is
still feasible, but would have to do in Hamburg already considerable
contortions in order to read the disc may lower.And last but not least: the
transverse axis of the dials are of course parallel to the latitude in the
east-west direction.
Nadivalaya
Yantra, is a version of an equinoctial sun dial quite different from the design
of the Samrat Yantra. The two circular plates that are facing the north and
south and are parallel to the axis of the rotation of Earth. The movement of
the shadow of these rods indicates the time. Jantar Mantar at Jaipur, built by
Maharaja Sawai Jai Singh II, is one of the largest stone observatories in the
world.
How the NadiValaya
Yantra works
If we take as a
reference an area parallel to latitude but perpendicular to the surface of the
earth at our location in the northern hemisphere, over the course of a year the
sun is more beyond that area than on this side. But if the plane is parallel to
the celestial equator and parallel to the degree of latitude, then the sun is
on the other side of the plane in the winter half-year, but on this side of the
plane in the summer half-year. This means that each of the two dials only gets
light for half a year, we have a winter disc for the period from March 21 to
September 22 for the phase of negative declination and a summer disc for the
period from September 22 to September 21 March for the phase of positive
declination.
At the
equinoxes, i.e. twice a year, on March 21st and September 21st, the declination
is 0°. If the sun moves exactly along the edge of the disc parallel to the
celestial equator, we theoretically (see below) have a shadow on both discs.
This is since the sun is not an infinitesimally small point, but due to its own
extension (30 arc minutes in the sky) in relation to the thickness of the
double sundial that day allows light to streak along both discs.
On these
equinoxes we have the longest shadow of the gnomon because the light streaks
flat. Conversely, we have the shortest shadow on the southern disc at the
winter solstice and the shortest shadow on the northern disc at the summer
solstice.
So, while the
angle of the shadow corresponds to the position of the sun over the course of
the day, the length of the shadow corresponds to the position of the sun over
the course of a half year. In the form of concentric circles, one can now
assign the individual signs of the zodiac in which the sun is located to the
length of the shadow.
On the north
side, the scale is divided into 24 segments of 1 hour each, with 12 at the top
and bottom and 6 on the right and left. Each lesson is divided into 2, then
further into 6 periods of 5 minutes each and further into 5 periods of 1 minute
each. The scale on the south side follows this pattern on the outside. Another
scale disc is engraved on the inside with an alternative division into 30
sections, the 1 is at the top and bottom, the 15 on the right and left, so we
get 60 sections of 1 ghati each = 24 minutes = 60 palas. 1 pala is 24 seconds
or 6 pranas. It follows that on the outer scale each degree equals 10 palas.
Daksinottara Bhitti Yantra
This instrument
measures the altitude or the angular height of a celestial object, when it
crosses the meridian.
Construction of
the instrument:
In a direct
extension of the gnomon of the Samrat Yantra is the north Dakshino Bhitti
Yantra (Yantra or Dakshinodak Bhitti), exactly in the north-south oriented.
There is a small, two-story, narrow rectangular building, climb a roof terrace
to a total of four flights, two of which can be arranged symmetrically. It is
no longer at the original location but was transferred stone by stone. The
decisive factor is the scale: On the west wall is a single, large, open top,
semi-circular scale with pointer is in the middle of the top edge. Each of the
above 0 degrees to 90 degrees on the scale is lower lows. Each Gard is once
again in 10 sections to a paladin and then again divided into three sections,
each 2 minutes. The stairs on the west wall in such a manner convenient to run
along below the scale that can be easily read. On the eastern wall (in front of
the drawing) are two quarter-circular scale (divided into 2 'sections) with two
each at the upper end of the intersecting scales. The division of the scale is
the same, it marks extend from 0 degrees to 90 degrees at the upper end at the
lower end, each 10 degrees with a number, each level is only at 10 and then
again divided into 3 sections. The two scales intersect at 60 degrees.
How the Dakshino
Bhitti Yantra work:
The instrument
is provided as the primary data only height values. Since the wall exactly north-south
direction and is the pointer shadow is very short, the instrument must be used
properly only at lunchtime, when the shadow is the longest. Then the shadow
shows the height of the sun at high noon on the scale. You can use this
instrument including summer and winter solstices and the achievement of the
equinoxes, and thus also display the progress of the seasons.
Unnatamsha
Yantra
Unnat: elevated,
Amsa: division, degree of arc. Unnatamsa is an instrument for measuring
altitude - the angular height of an object in the sky.
Fig: Unnatamsha Yantra
The large,
graduated brass circle hung from the supporting beam is the measuring
instrument of the Unnatamsa. The brass circle is pivoted to rotate freely
around a vertical axis.
Kapali Yantra
Kapila Yantra is
an instrument located in Jantar Mantar astronomical Museum in Jaipur,
Rajasthan. The Kapali Yantra device is used for solving the astronomical
problems graphically and to find out the Azimuth.
It consists of two sunken hemispheres (bowls). A map of the heavens is engraved on each bowl (a different map on each), showing the positions and motions of various heavenly bodies throughout the year.
Two wires (not
visible in this photo) are arranged to cross above the surface of the bowl. The
shadow of their intersection gives the position of the sun, projected onto the
celestial map engraved in the bowl. This allows the observer to determine the
position of the sun relative to the planets and zodiac at any time of the year,
for use in horoscopy and other astronomical calculations.
Rashivalaya
Yantras
The Rashivalaya
instruments were mentioned earlier as examples of sundials. However, their
orientation is unusual, since they do not point due north. This is a clue to
their purpose, which is to calculate sidereal, rather than solar, time. The
advantage of using sidereal coordinates is that they depend only on the annual
orbit of the earth around the sun, not on the earth's daily rotation.
Sidereal time is
measured relative to the ecliptic, the path of earth's orbit across the
heavens. The ecliptic is divided into 12 parts for convenience, each part named
after a constellation that is located there. The 12 constellations are called
the "Zodiac".
Chakra yantra
The Chakra
Yantra is the pair of upright metal circles in the photo. They stand between a
pair of hemispheres (bowl shapes) lowered into the ground in front of and
behind the metal circles. The pair of hemispheres is the Kapali Yantra,
discussed on the next page.
As for the
Chakra Yantra, it is an instrument for finding the right ascension and
declination of a planet or other celestial body observed at night.
To understand
these coordinates, it may help if you visualize the earth's lines of longitude
and latitude projected up onto the sky, such that the north star corresponds to
earth's north pole. Earthly latitude is the angular distance north or south of
the equator, and earthly longitude is the angular distance around the polar
axis as measured from any arbitrary starting point - in this case, the meridian
of Jaipur.
Current
Situation:
Our country
India is having such rich history not only cultural but astronomical also. A
history not based on assumptions but on shear calculations. In short, we say
the discoveries before the discoveries.
The truth is that we have more fascinators for Jantar mantar from foreign countries
than India itself. We must preserve these monuments and visit them, get inspire
and add to the legacy of our great nation.
Fig: The photo of planetary system in Jantar mantar
References:
https://architectuul.com/architecture/jantar-mantar
JantarMantar.com
Artandarcheology.com
https://upload.wikimedia.org/wikipedia/commons/b/b8/Jantar_Mantar%2C_New_Delhi_%28Misra_Yantra%29.jpg
Blog Credit:- Prajwal Kumbhar (Team Historic Wednesday)
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