Jantar Mantar Jaipur
¤ Jantar Mantar- Colossal
Observatory
Jantar Mantar, built between 1728 and 1734, literally means the ‘instruments
for measuring the harmony of the heavens’. Jai Singh, the brain
behind the grand project, chose stone with marble facing. This was the
biggest of all his observatories and the only one built of stone. He
used it daily, often with his astronomy gurus Pandit Jagannath and
Kewal Ram. In all there are 17 instruments in the Jantar Mantar
complex. The function of each instrument is rather complex but serves
a particular function where time plays the main theme.
¤ Instruments Used in Jantar Mantar
The instruments and their functions are given below in the order of
their anti-clockwise position in the complex. The large Kranti Yantra
was employed for the measurement of the longitude and latitude of the
celestial bodies. The Diganta Yantra was deviced to measure the
azimuth (arc of the celestial great circle from Zenith to horizon) of
planetary bodies. Similarly, the Small Ram Yantra and the Large Ram
Yantra are used to find the altitude and the azimuth. The Chakra
Yantra gives the angular measurement of an object from the equator.
The Jai Prakash Yantra determines the precise coordinates of celestial
bodies and the small iron plate strung between the crosswires gives
the sun’s longitude and latitude and the zodiacal sign that it is
passing through. Its main function is to keep an eye on all the other
instruments.
¤ Adequacy of Specific Yantras
The Rashivalayas Yantra operates in the same manner as that of the
Samrat Yantra and has one sundial for each of the zodiac signs. Five
of them (Gemini, Taurus, Cancer, Virgo and Leo) are at the back from
north to south. Aries and Libra face them followed by Aquarius,
Pisces, Capricorn, Scorpio and Sagittarius from north to south. It
helps in taking readings the moment each zodiacal sign crosses the
meridian. The Large Samrat Yantra is based on the same principle as
that of the small one but in size it is 10 times larger and more
accurate by 2 secs. The sundial is 27.4m high and is still used on the
Guru Purnima (full moon day in the month of Jul/Aug) to forecast the
onset of monsoon. The Dakshina Yantra is a wall is aligned along the
north-south meridian. It is mainly used to observe the position and
movement of the celestial bodies when they pass over the meridian.
The Disha Yantra has only one function and that is to point towards
the north. The Unnathamsa Yantra is used to find the altitudes of the
astral bodies. Observations can be made round the clock and the sunken
steps help in taking readings from any portion of the dial. The Raj
Yantra or the King of Instruments is used only once a year to
calculate the Hindu calendar, the details of which are based on the
Jaipur Standard. To do so a telescope is fixed over the central hole.
A bar for sighting is then attached at the back of the instrument. The
plain disk is used to record the sightings.The Observer’s Seat
belonged to Maharaja Jai Singh and was used for observing the wonders
of the sky and universe. The Narivalya Yantra is a sundial with two
dials; one facing north when the sun is in the Northern Hemisphere (21
Mar-21 Sep) and the other facing south for the rest of the year.
The Dhruva Yantra helps in finding the position of the Pole Star at
night and also those of the 12 zodiac signs. It is based on an
entirely different system to what is used today for the same purpose.
Traditionally, human breath, approximately of 6 secs was used as the
standard unit of measurement. The Small Samrat Yantra is a triangular
structure and has a large sundial with quadrants at the borders given
in hours and minutes. The arc on the left displays the time from
sunrise to midday and the one on the right from midday to sunset. The
sundials have been constructed on Latitude 27°N and the reading
can be adjusted to the Indian Standard Time (84°N) but that must
be done according to the month and the solar position.
Visiting Hours : 0930-1630
Hrs
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