Jantar Mantar

1
Jantar Mantarinstruments and formulae

• Jaipur, India

2
Commissioned by Emperor Muhammad Shah to correct
the existing astronomical tables and fix
planetary positions
3
Built by Sawai Jai Singh-II in 1728
4
The Jaiprakash Yantra
5
The Jaiprakash Yantra is in the form of two
hemispherical bowls representing the celestial
spheres
6
Each cavity is divided into six marble slabs,
divided further into minutes and seconds and
includes the signs of the zodiac
7
A disc suspended in the centre of each sphere
8
A disc suspended in the centre of each sphere,
produces a shadow on the instrument
9
From which you can read the position of the sun.
10
This instrument was the last to be built, is the
most accurate, and was used to test the other
instruments.
11
The Ram Yantra
12
The Ram Yantra is two marble cylinders, with a
rod mounted in the centre.
13
The position of the rods the shadow marks the
position of the sun, and thus the position of
celestial bodies
14
The twelve triangles are graduated from 90 45
degrees, and the walls are graduated from 45 0
degrees.
15
The Laghu Sanrat Yantra Small sun dial
16
On each side of gnomon, there are two quadrants.
The left for time in the morning and right for
the afternoon
17
The gnomon is at 27 degrees (about 1426Hrs here)
18
The quadrants are graduated into hours and
minutes, the minutes are graduated into 3rds
19
The Nariyalya Yantra
20
There are two faces to this sundial, parallel to
each other, one face is used when the sun is in
the northern hemisphere (21st March and 22nd
September)
21
Rashivalaya (Star Sign) Yantra
22
A group of 12 instruments, with graduated
quadrants on each side. The quadrants represent
the ecliptic.
23
When a zodiac reaches the local meridian the time
on the associated sun dial will be correct.
24
Yantra Raj (off screen)
25
Yantra Raj, only one of these is an instrument,
the other a blackboard!
26
Made of 7 alloys to prevent expansion and
contraction.
27
The hole in the centre is the position of Polaris.
28
Using the instrument it is possible to calculate
the dates of solar and lunar eclipses, Sun rise
set, moon rise and set etc.
29
The Samrat Yantra the King of all
instruments(its behind you!)
30
The largest Yantra, the gnomon is 89ft high and
148ft wide, the arches in the wall are to prevent
storm damage.
31
Accurate to 2 seconds local time, the Samrat is
still in use today for astronomy
32
And weather prediction A flag on the top shows
the wind direction and the coming of the monsoons
33
Other Yantras at the site (not my photos)
Chakra Yantra
Unnatasha Yantra
Digansa Yantra
Kranti Writa Yantra
34
Other Yantras at the site (not my photos)
Kapali Yantra
Dhakshinodak Bhitti Yantra
35
Thank you