JANTAR MANTARJai Singh's astronomical observatory may look like a giant playground for grownups, but in 1734, the year of its completion, it was the last outpost of medieval science. The observatory's eighteen fixed observational instruments are sighting devices which measure the position of the sun, stars and planets. Some are built entirely of masonry, others are engraved metal rings and plates set into masonry foundations.During the day, masonry sundials cast the sun's shadow on a suitably engraved scale. A sundial has two functional parts: agnomon, which is the part that casts the shadow, and ascale, from which the measurement is read. For example, in the instruments in the photo, the gnomon is an inclined ramp, and the scale is engraved on the circular part below the ramp. The sun, to the right, casts the gnomon's shadow on the curved scale to the left.Metal instruments are used for nighttime observations. They consist of a small sighting tube attached to a circular ring or plate which can pivot in various directions. They are operated by aiming the sighting tube directly at a planet or star, and then reading off its position from scales on the body of the instrument.Some instruments could be used for both daytime and nighttime observations. More information about this and other aspects of the observatory can be found in theAdditional Resourcesbelow.For all this to work, the position and orientation of the instruments and the calibration of their scales had to be minutely exact. The devices were built large, because the larger the scale, the more accurate the measurement. Once built and calibrated, they were fixed in place, could not be moved, and contained no moving parts (except of course for the pivots of the sighting instruments) or lenses. This restricted the kinds of observations that could be carried out, to those involving the positions and motions of the heavenly bodies which are visible to the naked eye.Such observations are no different in principle from those carried out in ancient Babylon, although they are considerably more accurate, and some of Jai Singh's instruments are original in design. Basically, however, this is how astronomy was done in early Mesopotamia, Egypt, Greece, China, and everywhere in the world, from the dawn of civilization down to the end of the Middle Ages.The projects carried out here included calculating the lunar calendar, predicting the start of the monsoon season, and creating astronomical tables. However, the observatory's main purpose seems to have been casting horoscopes, which requires a precise knowledge of the positions of the sun, moon, planets, and stars at the moment of birth.Because of the size and careful construction of these instruments, their accuracy was impressive by any standard. However, devices of this sort are expensive to construct. Once built, they can not be corrected or improved, and the kinds of observations they can make are limited, in the ways previously mentioned. Because of this, the instruments preserved here were conceptually obsolete even before their construction. They were soon overtaken in both usefulness and accuracy by the smaller machined brass instruments and telescopes of the modern era. Their lasting value is the tangible record they carry, a summing-up in mortar and stone of 2,500 years of premodern astronomy.

Jai SinghSawai Jai Singh, the first Maharaja of Jaipur, succeeded to the throne ofAmberin 1700 at the age of thirteen. Abandoning that capital, he founded the city of Jaipur in 1727. A soldier, ruler, and scholar with a lifelong interest in mathematics and astronomy, Jai Singh built observatories in Delhi, Jaipur, Ujjain, Mathura and Benares. Jai Singh was conversant with contemporary European astronomy through his contacts with the Portugese Viceroy in Goa. He supplied corrections to the astronomical tables of de la Hire, and published his own tables in 1723. The good state of preservation of the Jaipur observatory is due first of all to Chandra Dhar Sharma Guleri, who restored it in 1901. It has been well maintained from then to the present day.

Jantar MantarJantarmeans "instrument."Mantar(the same word as "mantra") is usually translated "formula," but here it means "calculation." So, "Jantar Mantar" means something like "instrument for calculation."

Additional ResourcesBasic Celestial Phenomena, by Kerry Magruder and Mike Keas. A good introduction to basic observational astronomy including the ecliptic, the celestial equator, and the zodiac.Jantar Mantar(1996), by Dr. Bonnie G. MacDougall at Cornell U. The Web version of an academic paper that places the observatory in its cultural context.Astronomical Instruments, from the Jiva Institute, discusses ten of the instruments and their mode of operation.Astronomical Observatory of Jaipur, by Daulat Singh Rajawat. Delta Publications, Jaipur, India. This book is sold near the observatory and elsewhere in Jaipur. It provides a useful and engaging description of the theory and practice of the observatory from a Vedic point of view.

Transcript 1. JANTAR MANTARJANTAR MANTARStone Astronomical ObservatoryStone Astronomical Observatory 2.Ancient India made some bigAncient India made some bigadvances in science becauseadvances in science becauseit was in constant contact withit was in constant contact withother countries. After theother countries. After theconquest of the Indus basin byconquest of the Indus basin byDarius around 520 B.C. IndiaDarius around 520 B.C. Indiawas thrown wide open towas thrown wide open toBabylonian influences.Babylonian influences.Through the Persians, IndiaThrough the Persians, Indiaalso came into contact withalso came into contact withGreece. All these contactsGreece. All these contactsgreatly helped India ingreatly helped India inenriching her sciences,enriching her sciences,particularly astronomy.particularly astronomy.Darius 3.There is ample evidence to show thatThere is ample evidence to show thatAryabhata (499 A.D.) and Varahamihira (6thAryabhata (499 A.D.) and Varahamihira (6thcentury A.D.) were well-acquainted withcentury A.D.) were well-acquainted withGreek astronomy.Greek astronomy.The most celebrated astronomers afterThe most celebrated astronomers afterVarahamihira were Brahmagupta (b.598Varahamihira were Brahmagupta (b.598A.D.), Lalla (8th cent.), Manjula or MunjalaA.D.), Lalla (8th cent.), Manjula or Munjala(10th cent.), Shripati (c.1039 A.D.) and(10th cent.), Shripati (c.1039 A.D.) andBhaskaracharya (b.1114 A.D.).Bhaskaracharya (b.1114 A.D.).In the post-Bhaskara period not muchIn the post-Bhaskara period not muchoriginal work in astronomy and mathematicsoriginal work in astronomy and mathematicswas done in India till modern times.was done in India till modern times.AryabhataAryabhataVarahamihiraVarahamihiraBhaskaracharyaBhaskaracharya 4. Nasir al-din at-Tusi (1201-1274 A.D.).Nasir al-din at-Tusi (1201-1274 A.D.).The last one was in- charge of theThe last one was in- charge of theobservatory at Maragha in Iran.observatory at Maragha in Iran.In 1420 A.D., Ulugh Begh, grandson ofIn 1420 A.D., Ulugh Begh, grandson ofTimur, built an observatory at Samarkand.Timur, built an observatory at Samarkand.Using very big but high-precisionUsing very big but high-precisioninstruments he prepared a Star catalogueinstruments he prepared a Star cataloguewhich was much better than that ofwhich was much better than that ofPtolemy.Ptolemy.SamarkandMaragha Omar Khayyam (1048-1124 A.D.)Omar Khayyam (1048-1124 A.D.) Al-Biruni (973-1848 A.D.)Al-Biruni (973-1848 A.D.) Al-Sufi ( 10th cent.)Al-Sufi ( 10th cent.) Tabit ibn Qurra (836-901 A.D.)Tabit ibn Qurra (836-901 A.D.) Al-Battani (850-929 A.D.)Al-Battani (850-929 A.D.) Al-Khwarismi (780-850 A.D.)Al-Khwarismi (780-850 A.D.)The Islamic world produced greatThe Islamic world produced greatmathematician-astronomers:mathematician-astronomers: 5. Later on he was appointed by MohammadLater on he was appointed by MohammadShah governor of the province of Agra andShah governor of the province of Agra andthen also of Malwa. From an early age Jaithen also of Malwa. From an early age JaiSingh was very much interested inSingh was very much interested inastronomical observations and hadastronomical observations and hadacquired thorough knowledge of itsacquired thorough knowledge of itsprinciples and rules.principles and rules. He was born in the ruling family of AmberHe was born in the ruling family of Amberin Rajasthan in 1686 A.D., one year afterin Rajasthan in 1686 A.D., one year afterNewton published his book Principia. HeNewton published his book Principia. Hesucceeded to the Amber throne at the agesucceeded to the Amber throne at the ageof thirteen.of thirteen. After a long time Sawai Jai Singh II was theAfter a long time Sawai Jai Singh II was theman from India who showed the greatestman from India who showed the greatestinterest in Arabic/Persian astronomy.interest in Arabic/Persian astronomy. 6. For observing the heavens Jai Singh builtFor observing the heavens Jai Singh builtobserv Jai Singh felt a great urge in reviving theJai Singh felt a great urge in reviving thestudy of astronomy in India. With the aim ofstudy of astronomy in India. With the aim ofpreparingpreparing new tables, Jai Singh at firstnew tables, Jai Singh at firststarted with the traditional brassstarted with the traditional brassinstruments. Realising their inadequacy, heinstruments. Realising their inadequacy, hediscarded them in favour of stone anddiscarded them in favour of stone andmasonry instruments of huge size.masonry instruments of huge size.atories at five places :observatories at five places : Delhi,Delhi,Jaipur, Mathura, Ujjain andJaipur, Mathura, Ujjain andVaranasi.Varanasi. The first one was built in DelhiThe first one was built in Delhiin year around 1724. These observatories,in year around 1724. These observatories,which in course of time came to be calledwhich in course of time came to be calledJantar Mantar, housed a wide variety ofJantar Mantar, housed a wide variety ofmasonry and metal instruments.masonry and metal instruments. 7. Jai Singhs court astronomer Pt.Jagannatha, who hadJai Singhs court astronomer Pt.Jagannatha, who hadmastered in Arabic and Persian, translated from Arabicmastered in Arabic and Persian, translated from Arabicinto Sanskrit works titled Rekhaganita and Siddhanta-into Sanskrit works titled Rekhaganita and Siddhanta-Samrata. The translation of the former was completed inSamrata. The translation of the former was completed in1718 A.D. and of the latter in 1731 A.D.1718 A.D. and of the latter in 1731 A.D. Jai Singh, making use of the masonry and metalJai Singh, making use of the masonry and metalinstruments of his observatories, prepared theinstruments of his observatories, prepared theastronomical treatise Zij-I -Muhammad Shah andastronomical treatise Zij-I -Muhammad Shah anddedicated it to the reigning monarch Muhammad Shah.dedicated it to the reigning monarch Muhammad Shah.The work was completed around 1727-28 A.D.The work was completed around 1727-28 A.D. 8. Jai Singh want to determine newJai Singh want to determine newplanetary constants but his primaryplanetary constants but his primaryinterests in astronomy centered on theinterests in astronomy centered on themoon. He was more interested inmoon. He was more interested inobserving and mathematically predictingobserving and mathematically predictingthe position of this heavenly body. He wasthe position of this heavenly body. He wasalso interested in the prediction of Solaralso interested in the prediction of Solareclipses and in calculation of theeclipses and in calculation of theoccultation of stars and planets by theoccultation of stars and planets by themoon.moon. Jai Singh had established contacts withJai Singh had established contacts withJesuit missionaries in India and had alsoJesuit missionaries in India and had alsoknown the telescope. But he did not makeknown the telescope. But he did not makeuse of the Copernican revolution ushereduse of the Copernican revolution usheredin Europe. He remained a firm follower ofin Europe. He remained a firm follower ofthe geocentric system of Indian traditionthe geocentric system of Indian traditionand of Ptolemy. It seems that Jai Singhand of Ptolemy. It seems that Jai Singhhad no knowledge of the works of Keplerhad no knowledge of the works of Kepler(1571-1630) or Newton (1642-1727).(1571-1630) or Newton (1642-1727). 9. High precision Masonary InstrumentsHigh precision Masonary Instruments Medium precision Masonary InstrumentsMedium precision Masonary Instruments Low precision Masonary InstrumentsLow precision Masonary InstrumentsJai Singh constructed 15 different types ofinstruments of masonry for his observatories. Outof these fifteen he himself invented seveninstruments. According to the precession of theinstruments it can be divide in followingcategories: 10.Jai Singh Low precision Masonary InstrumentsJai Singh Low precision Masonary InstrumentsInstrumentInstrument NumberNumber LocationLocationDhruvadarsakaDhruvadarsaka 11 JaipurJaipurNadivalayaNadivalaya 55 Jaipur,Varanasi,Ujjain,Mathura,Jaipur,Varanasi,Ujjain,Mathura,UjjainUjjainPalabhaPalabha 22 Jaipur UjjainJaipur UjjainAgraAgra 55 Jaipur,Varanasi,Ujjain,Mathura,UjjainJaipur,Varanasi,Ujjain,Mathura,UjjainSankuSanku 11 MathuraMathuraUnknown InstrumentUnknown Instrument 11 VaranasiVaranasi 11.Jai singh Medium precision Masonary InstrumentsJai singh Medium precision Masonary InstrumentsInstrumentInstrument NumberNumber LocationLocationJaiPrakasaJaiPrakasa 22 Delhi, JaipurDelhi, JaipurRama YantraRama Yantra 22 Delhi, JaipurDelhi, JaipurRasi ValayaRasi Valaya 1212 JaipurJaipurSara YantraSara Yantra 11 JaipurJaipurDigamsaDigamsa 33 Varanasi,Ujjain,JaipurVaranasi,Ujjain,JaipurKapalaKapala 22 JaipurJaipur 12.Jai singh High precision Masonary InstrumentsJai singh High precision Masonary InstrumentsInstrumentInstrument NumberNumber LocationLocationSamratSamrat66 Delhi,Jaipur(2),Ujjain,Varanasi(2)Delhi,Jaipur(2),Ujjain,Varanasi(2)SasthamsaSasthamsa55 Delhi, Jaipur(4)Delhi, Jaipur(4)Daksinottara BhittiDaksinottara Bhitti66 Jaipur,Varanasi(2),Ujjain,Mathura,Jaipur,Varanasi(2),Ujjain,Mathura,DelhiDelhi 13.Instruments added after Jai SinghInstruments added after Jai SinghInstrumentInstrument NumberNumber LocationLocationMishra YantraMishra Yantra 11 DelhiDelhiSanku YantraSanku Yantra 11 UjjainUjjainHorizontal ScaleHorizontal Scale 11 JaipurJaipur 14.Measurements Related TermsMeasurements Related TermsAzimuth:Azimuth: AzimuthAzimuth isisgenerally defined as agenerally defined as ahorizontal angle measuredhorizontal angle measuredclockwise from any fixedclockwise from any fixedreference plane.In modernreference plane.In modernastronomy it is nearlyastronomy it is nearlyalways measured clockwisealways measured clockwisefrom the north base line orfrom the north base line ormeridian. It measured inmeridian. It measured indegree and tells about thedegree and tells about thedirection of a celestial bodydirection of a celestial bodyfrom the observer.from the observer. 15.Measurements Related TermsMeasurements Related TermsAltitude: As a generalAltitude: As a generaldefinition, altitude is adefinition, altitude is adistance measurement,distance measurement,usually in the vertical orusually in the vertical or"up" direction, between a"up" direction, between areference line and a pointreference line and a pointor object. The referenceor object. The referenceline also often variesline also often variesaccording to the context.according to the context. 16. Zenith Distance:Zenith Distance: In general terms, theIn general terms, the zenithzenith is the directionis the directionpointing directly "above" a particular location . The conceptpointing directly "above" a particular location . The conceptof "above" is more specifically defined in astronomy,of "above" is more specifically defined in astronomy,geophysics as the vertical direction opposite to the force ofgeophysics as the vertical direction opposite to the force ofgravity at a given location. The opposite direction, i.e. thegravity at a given location. The opposite direction, i.e. thedirection of the gravitational force is called the nadir. Thedirection of the gravitational force is called the nadir. Theterm zenith is also used to represent the highest pointterm zenith is also used to represent the highest pointreached by a celestial body during its apparent orbit aroundreached by a celestial body during its apparent orbit arounda given point of observation.a given point of observation. MeridianMeridian : A: A meridianmeridian (or(or line of longitudeline of longitude) is an) is animaginary arc on the Earths surface from the North Pole toimaginary arc on the Earths surface from the North Pole tothe South Pole that connects all locations running along itthe South Pole that connects all locations running along itwith a given longitude. The position of a point on thewith a given longitude. The position of a point on themeridian is given by the latitude .meridian is given by the latitude .Measurements Related TermsMeasurements Related Terms 17.Hour AngleHour Angle: In astronomy, the: In astronomy, the hour anglehour angle is one of the coordinatesis one of the coordinatesused in the equatorial coordinate system for describing the position ofused in the equatorial coordinate system for describing the position ofa point on the celestial sphere. The hour angle of a point is the anglea point on the celestial sphere. The hour angle of a point is the anglebetween the half plane determined by the Earth axis and the zenithbetween the half plane determined by the Earth axis and the zenith(half of the meridian plane) and the half plane determined by the(half of the meridian plane) and the half plane determined by theEarth axis and the given point. The angle is taken with minus sign ifEarth axis and the given point. The angle is taken with minus sign ifthe point is eastward of the meridian plane and with the plus sign ifthe point is eastward of the meridian plane and with the plus sign ifthe point is westward of the meridian planethe point is westward of the meridian planeLatitudeLatitude:: LatitudeLatitude, usually denoted by the Greek letter phi (, usually denoted by the Greek letter phi () gives) givesthe location of a place on Earth (or other planetary body) north orthe location of a place on Earth (or other planetary body) north orsouth of the equator. Technically, latitude is an angular measurementsouth of the equator. Technically, latitude is an angular measurementin degrees (marked with ) ranging from 0 at the equator (lowin degrees (marked with ) ranging from 0 at the equator (lowlatitude) to 90 at the poles (90 N or +90 for the North Pole and 90latitude) to 90 at the poles (90 N or +90 for the North Pole and 90S or 90 for the South Pole).S or 90 for the South Pole). 18.EquinoxEquinox : An: An equinoxequinox occurs twice a year, when the tilt of theoccurs twice a year, when the tilt of theEarths axis is inclined neither away from nor towards the Sun,Earths axis is inclined neither away from nor towards the Sun,the Sun being vertically above a point on the Equator. The termthe Sun being vertically above a point on the Equator. The termequinoxequinox can also be used in a broader sense, meaning the datecan also be used in a broader sense, meaning the datewhen such a passage happens. The name "equinox" is derivedwhen such a passage happens. The name "equinox" is derivedfrom the Latinfrom the Latin aequusaequus (equal) and(equal) and noxnox (night), because around(night), because aroundthe equinox, the night and day are approximately equally long.the equinox, the night and day are approximately equally long.EclipticEcliptic TheThe eclipticecliptic is the apparent path that the Sun tracesis the apparent path that the Sun tracesout in the sky during the year. As it appears to move in theout in the sky during the year. As it appears to move in thesky in relation to the stars, the apparent path aligns with thesky in relation to the stars, the apparent path aligns with theplanets throughout the course of the year. More accurately, itplanets throughout the course of the year. More accurately, itis the intersection of a spherical surface, the celestial sphere,is the intersection of a spherical surface, the celestial sphere,with thewith the ecliptic planeecliptic plane.. 19. Equator :Equator : TheThe equatorequator (sometimes referre Angle of Declination:Angle of Declination: Angle at a particular point on the EarthsAngle at a particular point on the Earthssurface between the direction of the true or geographic Northsurface between the direction of the true or geographic NorthPole and the magnetic north pole. The angle of declinationPole and the magnetic north pole. The angle of declinationhas varied over time because of the slow drift in the positionhas varied over time because of the slow drift in the positionof the magnetic north pole.of the magnetic north pole.d to colloquially as(sometimes referred to colloquially as"the Line""the Line") is the intersection of the Earths surface with the) is the intersection of the Earths surface with theplane perpendicular to the Earths axis of rotation andplane perpendicular to the Earths axis of rotation andcontaining the Earths center of mass. In simpler language, itcontaining the Earths center of mass. In simpler language, itis an imaginary line on the Earths surface approximatelyis an imaginary line on the Earths surface approximatelyequidistant from the North Pole and South Pole that dividesequidistant from the North Pole and South Pole that dividesthe Earth into a Northern Hemisphere and a Southernthe Earth into a Northern Hemisphere and a SouthernHemisphere.Hemisphere. 20.JANTAR MANTAR DELHI 21.Mishra YantraMishra YantraSamarat GnomonQuadrantSecondQuadrantSamarat GnomonNiyata Cakra 22.Mishra YantraMishra YantraMishra Yantra consists of several instruments within the singleMishra Yantra consists of several instruments within the singlestructure. The instruments included in the structure are asstructure. The instruments included in the structure are asfollowsfollows::1.Daksinottra Bhitti1.Daksinottra Bhitti : for measuring the zenith distance or: for measuring the zenith distance oraltitude of sun and other planets.altitude of sun and other planets.2.Karkarasi Valaya::2.Karkarasi Valaya:: Instrument is now in ruins. Application isInstrument is now in ruins. Application isnot known and according to the theory it was used to measurenot known and according to the theory it was used to measuredirectly the longitude of celestial body.directly the longitude of celestial body.3.Samarat Yantra3.Samarat Yantra : for measuring the local time.: for measuring the local time.4. Niyata Cakras:4. Niyata Cakras: for measuring the declination of an object atfor measuring the declination of an object atinterval of a few hours as the object travels from east to west ininterval of a few hours as the object travels from east to west inthe sky.the sky.5. Quadrant arc5. Quadrant arc of unknown functionof unknown function 23.Samarat YantraSamarat Yantra 24. In addition to marking local time the Samarat YantraIn addition to marking local time the Samarat Yantrawas used to determine the sun declination and thewas used to determine the sun declination and theright ascension of any celestial object.right ascension of any celestial object. By knowing the time of the meridian transit ofBy knowing the time of the meridian transit ofprominent star and observing the hour angle of theprominent star and observing the hour angle of thestar or its angular distance from meridian time atstar or its angular distance from meridian time atnight may also calculated from this instrument.night may also calculated from this instrument. The primary object of Samarat is to indicate the solarThe primary object of Samarat is to indicate the solartime or local time of a place.time or local time of a place.Samarat YantraSamarat Yantra 25.Jai Prakesh YantraJai Prakesh Yantra 26. The instrument can measure the local co-ordinates of aThe instrument can measure the local co-ordinates of acelestial object - the Altitude and Azimuth.celestial object - the Altitude and Azimuth. Cross wires are stretched in the North-South and East-WestCross wires are stretched in the North-South and East-Westdirection on the surface of the instrument bowls. Shadow of thedirection on the surface of the instrument bowls. Shadow of thecentre of this cross wire, on the surface of the bowl, shows thecentre of this cross wire, on the surface of the bowl, shows theposition of the Sun in the sky.position of the Sun in the sky. Twin hemispherical bowls of Jai Prakas yantra are each aTwin hemispherical bowls of Jai Prakas yantra are each areflection of the sky above. The bowls are marked in sectorsreflection of the sky above. The bowls are marked in sectorsand gaps. Observers move inside the gap regions and makeand gaps. Observers move inside the gap regions and makeobservations using the markings on the sectors. Theobservations using the markings on the sectors. Theinstruments are complimentary, in the sense that where there isinstruments are complimentary, in the sense that where there isa gap in one of the bowl, is a sector placed in the other bowla gap in one of the bowl, is a sector placed in the other bowland vice versa. Spliced together, they make a whole bowl thatand vice versa. Spliced together, they make a whole bowl thatis a complete reflection of the sky above.is a complete reflection of the sky above.Jai Prakash YantraJai Prakash Yantra 27.Rama YantraRama Yantra 28.Jantar MantarJantar MantarJaipurJaipur 29.Jaipur, Jantar Mantar was the second and more sophisticatedJaipur, Jantar Mantar was the second and more sophisticatedobservatory Jai singh built.The instruments were so big andobservatory Jai singh built.The instruments were so big andaccurate ,as they were built of stone,masonry and marble.accurate ,as they were built of stone,masonry and marble.There are 18 instruments in the Jaipur observatory. HeThere are 18 instruments in the Jaipur observatory. Heprocured latest astronomical books and instruments fromprocured latest astronomical books and instruments fromEurope.Some he had translated in Sanskrit.Some of theseEurope.Some he had translated in Sanskrit.Some of thesetranslated texts are on display in the City Palace Museum.translated texts are on display in the City Palace Museum. 30.Samrat YantraSamrat YantraBy far the biggest yantra in Jantar Mantar. it is a huge SunBy far the biggest yantra in Jantar Mantar. it is a huge SunDial. It is 89 feet high and 148 feet wide. It can measureDial. It is 89 feet high and 148 feet wide. It can measurelocal time correctly up to 2 seconds..local time correctly up to 2 seconds.. 31.Chakra YantraChakra Yantra 32. For measuring the declination and hour angle of an object,For measuring the declination and hour angle of an object,a sighting tube is mounted at the centre of the instrument.a sighting tube is mounted at the centre of the instrument.The tube with a pointer attached to it, rotates about aThe tube with a pointer attached to it, rotates about aperpendicular axis passing through the centre of cakraperpendicular axis passing through the centre of cakraring. The observer rotating the cakra about its polar axisring. The observer rotating the cakra about its polar axisand the tube about the centre obtains the object in sightand the tube about the centre obtains the object in sightand the hour angle off the plate at the post.and the hour angle off the plate at the post. The Jaipur observatory has two unit of Cakra Yantra.The Jaipur observatory has two unit of Cakra Yantra.Instrument is made of heavy molded brass and pivoted toInstrument is made of heavy molded brass and pivoted torotate freely about a diameter parallel to the earth axis.rotate freely about a diameter parallel to the earth axis.Objective of the instrument is to measure the declinationObjective of the instrument is to measure the declinationand hour angle of celestial body.and hour angle of celestial body. 33.Rashivalaya YantraRashivalaya Yantra 34.There are 12 signs of the zodiac, so there are 12There are 12 signs of the zodiac, so there are 12Rasivalayas representing each sign.Rasivalayas representing each sign.At that moment its gnomon point towards the pole ofAt that moment its gnomon point towards the pole ofecliptic and its guardant become parallel to the ecliptic.ecliptic and its guardant become parallel to the ecliptic.Rasivalaya were also invented by Jai Singh. A particularRasivalaya were also invented by Jai Singh. A particularRasivalaya instrument become operative when first pointRasivalaya instrument become operative when first pointof sign of the zodiac it represents approaches theof sign of the zodiac it represents approaches themeridian.meridian.The Rasivalaya are a set of 12 instruments based on theThe Rasivalaya are a set of 12 instruments based on theprinciple of samarat yantra are designed for directlyprinciple of samarat yantra are designed for directlymeasuring the latitude and longitude of a celestial object.measuring the latitude and longitude of a celestial object. 35.Narivalaya YantraNarivalaya Yantra 36. On the vernal equinox and the autumnal equinoxOn the vernal equinox and the autumnal equinoxthe rays of the sun fall parallel to two opposingthe rays of the sun fall parallel to two opposingfaces This is an effective tool for demonstrating theThis is an effective tool for demonstrating thepassage of sun across the celestial equator.passage of sun across the celestial equator. Jai Singh built Nadivalays at each hisJai Singh built Nadivalays at each hisobservatory site except Delhi.observatory site except Delhi. After the sun has crossed the equator around 21After the sun has crossed the equator around 21March its illuminate the northern face for sixthMarch its illuminate the northern face for sixthmonths. After 21 September it is the southernmonths. After 21 September it is the southernface that receives the rays of the sun for the nextface that receives the rays of the sun for the nextsix months.six months.of plates and illuminate them both. Otherfaces of plates and illuminate them both. Othertime only one or other face remains in the sun.time only one or other face remains in the sun. 37. The main function of theThe main function of theinstrument is to measure time.instrument is to measure time. This is the largest instrumentThis is the largest instrumentin the world for its kind.in the world for its kind.Instrument is built for theInstrument is built for thelatitude of Jaipur as there arelatitude of Jaipur as there are27 degree making between the27 degree making between thezenith and the pole.zenith and the pole. Orientation of the pillars isOrientation of the pillars issuch that the line joining themsuch that the line joining themmakes an angle of about 23makes an angle of about 23degree with the plane ofdegree with the plane ofmeridian.meridian. Great astrolabe is suspendedGreat astrolabe is suspendedfrom massive wooden beamfrom massive wooden beamsupported by tall pillars.supported by tall pillars.Yantra RajYantra Raj 38.Krantiwrita YantraKrantiwrita YantraThis is the unfinished structure and has twoThis is the unfinished structure and has twocircular plates. Both the plates have a scalecircular plates. Both the plates have a scalewhich is divide in degrees.which is divide in degrees. 39.Unnatasha YantraUnnatasha Yantra 40.The rim of the brass circle has graduations marked in such away that smallest division is a tenth of a degree. The largerdivisions of 1 degree and of 6 degrees are also marked on thecircle. After sighting the celestial object, its Altitude can be readfrom the position of the pointer.The large graduated brass circle hung from the supportingbeam, is the measuring instrument of the Unnatamsa. The brasscircle is pivoted to rotate freely around a vertical axis. The ring hastwo cross beams in the vertical and horizontal directions. Asighting tube is pivoted at the centre of the circle, which can bemoved in the vertical direction, to align towards any celestialobject.Unnatamsa can measure the Altitude of a celestial object. 41.Dakshinodak Bhitti YantraDakshinodak Bhitti Yantra 42.Daksinottara BittiDaksinottara BittiDaksinottara Bitti yantra consists of aDaksinottara Bitti yantra consists of agraduated quadrant or a semicircle inscribedgraduated quadrant or a semicircle inscribedon a north-south wall. At the centre of the areon a north-south wall. At the centre of the areis a horizontal rod. The instrument is used foris a horizontal rod. The instrument is used formeasuring the meridian attitude or the zenithmeasuring the meridian attitude or the zenithdistance of an object such as the sun, the moondistance of an object such as the sun, the moonor a planet.or a planet. 43.Jai Prakash YantraJai Prakash Yantra 44.Kapala YantraKapala Yantra 45. By looking at the shadow of a cross wire stretchedBy looking at the shadow of a cross wire stretchedover its surface, the co-ordinates of the Sun in theover its surface, the co-ordinates of the Sun in thesky, can be determined with the western Kapalask The western Kapala unit is built for observations whileThe western Kapala unit is built for observations whilethe eastern segment is meant for theoreticalthe eastern segment is meant for theoreticalconversions of co-ordinates from one system toconversions of co-ordinates from one system toanother. The western Kapala unit is analogous to theanother. The western Kapala unit is analogous to theJaiprakas a hemispherical bowl on which everyJaiprakas a hemispherical bowl on which everypoint is a reflection of a point in the sky.point is a reflection of a point in the sky. The Kapala are built as two hemispherical units, eachThe Kapala are built as two hemispherical units, eachhemisphere being a complete reflection of the skyhemisphere being a complete reflection of the skyoverhead.overhead.y, can be determined with the western Kapala.. 46.One difference between the two instruments is that Kapalaindicates the a ppp while Jay Praksa observe the sign of meridian.Another is that Jay Praksa built in two complementary halves,These arcs indicate the local time and they measureastronomical parameter,such as co-ordinates of celestial body.Jai Praksa and the Kapala are both multipurpose instrumentsconsisting of hemispherical surface of concave shape andinscribed width of number of arcs.The yantra hare a diameter of 3.46 m each and are so namedbecause by there resemblance to the brain cover of human skill. 47.Ram YantraRam Yantra 48. The coordinates of the moon when it is bright enough toThe coordinates of the moon when it is bright enough tocast a shadow, may also be read in a similar manner.cast a shadow, may also be read in a similar manner. In day time the coordinates of a sun are determined byIn day time the coordinates of a sun are determined byobserving the shadow of the pillar top end on the scales.observing the shadow of the pillar top end on the scales. For measuring the azimuth, circular scales with theirFor measuring the azimuth, circular scales with theircentre at the axis of cylindrical walls. The scales arecentre at the axis of cylindrical walls. The scales aredivided into degree and minutes.divided into degree and minutes. Cylindrical structure of Rama Yantra is open at the topCylindrical structure of Rama Yantra is open at the topand its height equals its radius.and its height equals its radius. This yantra is used to measure the azimuth and altitudeThis yantra is used to measure the azimuth and altitudeof a celestial object, for example sun.of a celestial object, for example sun. The Rama yantra, probably named after Rama SinghThe Rama yantra, probably named after Rama SinghThe grandfather of Jai Singh.The grandfather of Jai Singh. 49.JANTAR MANTAR UJJAINJANTAR MANTAR UJJAIN 50.Daksinottara BittiDaksinottara Bitti 51.Daksinottara BittiDaksinottara BittiDaksinottara Bitti yantra consists of aDaksinottara Bitti yantra consists of agraduated quadrant or a semicircle inscribedgraduated quadrant or a semicircle inscribedon a north-south wall. At the centre of the areon a north-south wall. At the centre of the areis a horizontal rod. The instrument is used foris a horizontal rod. The instrument is used formeasuring the meridian attitude or the zenithmeasuring the meridian attitude or the zenithdistance of an object such as the sun, the moondistance of an object such as the sun, the moonor a planet.or a planet. 52.Samarat YantraSamarat Yantra 53.SANKUDIGAMASA 54. Cross wires are stretched between the coordinal points markedCross wires are stretched between the coordinal points markedover the outer wall. The observer uses one or more stringsover the outer wall. The observer uses one or more stringswith one end tied to a knob on the pillar and other end to stonewith one end tied to a knob on the pillar and other end to stonepebbles suspended over the walls, with these strings thepebbles suspended over the walls, with these strings theobserver defines a vertical plane contain the cross wire and theobserver defines a vertical plane contain the cross wire and theobject in the sky. The angular distance of the vertical planeobject in the sky. The angular distance of the vertical planefrom the north point, read on the scales indicate the azimuth offrom the north point, read on the scales indicate the azimuth ofbody.body. Its centre pillar as well as its wall are engraved in degrees andIts centre pillar as well as its wall are engraved in degrees andnumbers at their top level.numbers at their top level. This consists of two cylindrical wall surrounding a centreThis consists of two cylindrical wall surrounding a centrepillar measure the angle of azimuth of a celestial body.pillar measure the angle of azimuth of a celestial body.Digmasa YantraDigmasa Yantra 55.Jantar Mantar at VaranasiJantar Mantar at Varanasi 56.Some Glimpses of Jantar Mantar Varanasi 57.Some Glimpses of Jantar Mantar Varanasi 58. Unidentified structureUnidentified structure Daksinottara BhittiDaksinottara Bhitti Cakra YantraCakra Yantra NadivalayaNadivalaya DigamsaDigamsa Samarat YantraSamarat YantraJantar Mantar at VaranasiJantar Mantar at VaranasiObservatory at Vanarasi has following Instruments:Observatory at Vanarasi has following Instruments: 59.SMRAT YANTRA -------->