{{short description|UNESCO World Heritage Site in Jaipur}}
{{Other uses|Jantar Mantar (disambiguation)}}
{{Use dmy dates|date=June 2016}}{{Use Indian English|date=June 2016}}
{{Infobox historic site
| name = Jantar Mantar
| built = 1728–{{start date and age|1734}}
| image = Jantar Mantar at Jaipur.jpg
| image_upright = 1.2
| caption = 
| location = [[Jaipur]], Rajasthan, India
| coordinates = {{coord|26.92472|N|75.82444|E|type:landmark_region:IN|format=dms|display=inline,title}}
| area = {{convert|1.8652|ha|acre|abbr=on}}
| governing_body = [[Government of Rajasthan]]
| pushpin_map = India Jaipur
| pushpin_caption = Location of Jantar Mantar in Jaipur
| designation1 = WHS
| designation1_offname = The Jantar Mantar, Jaipur
| designation1_date = [[List of World Heritage Sites by year of inscription#2010 (34th session)|2010]] <small>(34th [[World Heritage Committee|session]])</small>
| designation1_criteria = {{UNESCO WHS type|(iii), (iv)}}(iii), (iv)
| designation1_number = [https://whc.unesco.org/en/list/1338 1338]
| designation1_free1name = Region
| designation1_free1value = [[List of World Heritage Sites in Southern Asia|Southern Asia]]
}}
[[File:Jantar Mantar, Jaipur India.jpg|thumb|Jantar Mantar, Jaipur]]
The '''Jantar Mantar''' is a collection of 19 astronomical instruments built by the [[Rajput]] king [[Sawai Jai Singh]], the founder of [[Jaipur]], Rajasthan, India. The monument was completed in 1734.<ref name=unesco/><ref name=portal>[http://www2.astronomicalheritage.net/index.php/show-entity?idunescowhc=1338 The Jantar Mantar at Jaipur, India] {{Webarchive|url=https://web.archive.org/web/20200622184202/https://www3.astronomicalheritage.net/index.php/show-entity?idunescowhc=1338 |date=22 June 2020 }} Portal to the Heritage of Astronomy, in partnership with UNESCO World Heritage Site</ref> It features the world's largest stone [[sundial]], and is a [[UNESCO]] [[World Heritage Site]].<ref name=unesco>{{cite web|url=https://whc.unesco.org/en/list/1338 |title=The Jantar Mantar, Jaipur - UNESCO World Heritage Centre |publisher=Whc.unesco.org |date=31 July 2010 |access-date=11 November 2012}}</ref><ref name=smithsonian>{{cite book|last1=Smithsonian|title=Timelines of Science|publisher=Penguin|isbn=978-1465414342|page=136}}</ref> It is near [[City Palace, Jaipur|City Palace]] and [[Hawa Mahal]].<ref name="ohashi1">{{cite book|last1=Yukio Ohashi|editor= H Selin|editor-link=Helaine Selin|title=[[Encyclopaedia of the History of Science, Technology, and Medicine in Non-Western Cultures]]|date=1997|publisher=Springer|isbn=978-0792340669|pages=83–86}}</ref> The instruments allow the observation of astronomical positions with the naked eye.<ref name="unesco" /> The observatory is an example of the Ptolemaic positional astronomy which was shared by many civilizations.<ref name="unesco" /><ref name="portal" />

The monument features instruments operating in each of the three main classical [[Astronomical coordinate systems|celestial coordinate systems]]: the horizon-zenith local system, the equatorial system, and the ecliptic system.<ref name=portal/> The ''Kanmala Yantraprakara'' is one that works in two systems and allows the transformation of the coordinates directly from one system to the other.<ref name=kapala1>{{cite journal|last1=Sharma|first1=VN|title=The Kapala Yantras of Sawai Jai Singh|journal=Indian Journal of History of Science|date=1991|volume=26|issue=2|pages=209–216|url=http://www.new1.dli.ernet.in/data1/upload/insa/INSA_1/20005ac0_209.pdf|url-status=dead|archive-url=https://web.archive.org/web/20150505180940/http://www.new1.dli.ernet.in/data1/upload/insa/INSA_1/20005ac0_209.pdf|archive-date=5 May 2015|df=dmy-all}}</ref> It has the biggest [[sundial]] in the world.

The monument was damaged in the 19th century. Early restoration work was undertaken under the supervision of [[Major (rank)|Major]] [[Arthur Barrett (Indian Army officer)|Arthur Garrett]], a keen amateur astronomer, during his appointment as Assistant State Engineer for the Jaipur District.<ref>[[Monthly Notices of the Royal Astronomical Society]], Vol. 81, p. 257</ref> UNESCO describes the observatory as the most significant and best-preserved historic observatory in India, representing the astronomical and cosmological knowledge of the late [[Mughal Empire]].<ref name="unesco"/>

==Name==
The name ''jantar'' is derived from ''yantra'', a [[Sanskrit]] word meaning "instrument, machine", and ''mantar'' from ''mantrana'', also a Sanskrit word meaning "consult, calculate".<ref name="SpokenSanskrit">{{cite web|title=Sanskrit - English Dictionary|url=http://spokensanskrit.de/index.php?script=HK&beginning=0+&tinput=&trans=Translate&direction=AU|website=Spoken Sanskrit Germany|publisher=Koln University|access-date=15 April 2015}}</ref>{{rp|at=mantraNa, yantra}} Therefore, ''Jantar Mantar'' literally means 'calculating instrument'.<ref name=smithsonian/>
[[File:Jaipur, Jantar Mantar, Brihat Samrat Yantra (9713595658).jpg|250px|thumb|Brihat Samrat Yantra|left]]

== Purpose ==
Jai Singh noticed that the [[Zij]], which was used for determining the position of celestial objects, did not match the positions calculated on the table. He constructed five new observatories in different cities in order to create a more accurate Zij. The astronomical tables Jai Singh created, known as the Zij-i Muhammad Shahi, were continuously used in India for a century. (However, the table had little significance outside of India.) Also, it was used to measure time.<ref name=":0">{{Cite book|title=Sawai Jai Singh and his astronomy|last=Nath.|first=Sharma, Virendra|date=2016|publisher=Motilal Banarsidass Publishers|others=Jai Singh II, Maharaja of Jaipur, 1686-1743.|isbn=978-81-208-1256-7|edition= 2nd|location=Delhi|oclc=32699670}}</ref>

== History ==
Exactly when [[Sawai Jai Singh]] began construction in [[Jaipur]] is unknown, but several instruments had been built by 1728, and the construction of the instruments in Jaipur continued until 1738. During 1735, when construction was at its peak, at least 23 astronomers were employed in Jaipur, and due to the changing political climate, Jaipur replaced [[Delhi]] as Raja Jai Singh's main observatory and remained Jai Singh's central observatory until his death in 1743. The observatory lost support under [[Ishwari Singh of Jaipur|Ishwari Singh]] (r.1743-1750) because of a succession war between him and his brother. However, [[Madho Singh I]] (r. 1750–1768), Ishwari Singh's successor, supported the observatory, although it did not see the same level of activity as under Jai Singh. Although some restorations were made to the Jantar Mantar under Pratap Singh (r.1778-1803), activity at the observatory died down again. During this time, a temple was constructed and Pratap Singh turned the site of the observatory into a gun factory.<ref>{{Cite journal |last=Johnson-Roehr |first=Susan N. |date=2014 |title=Observatories of Sawai Jai Singh II |url=https://www.academia.edu/43023913/Observatories_of_Sawai_Jai_Singh_II |journal=Handbook of Archaeoastronomy and Ethnoastronomy |pages=2017}}</ref>

[[File:Bhairav Temple Jantar Mantar Jaipur.jpg|thumb|Bhairav Temple - located within the Jantar Mantar Complex]]
Ram Singh (r. 1835–1880) completed restoring the Jantar Mantar in 1876, and even made some of the instruments more durable by inserting lead into the instruments' lines and using stone to restore some of the plaster instruments. However, the observatory soon became neglected again, and was not restored until 1901 under [[Madho Singh II]] (r. 1880–1922) <ref name=":0" />

==Description==
[[File:Ecliptic equator galactic anim.gif|thumb|Jantar Mantar deploys all three ancient coordinate systems of the five celestial coordinate systems known. In the image above, the red ([[ecliptic]]) and blue ([[Equator|equatorial]]) coordinate systems are two of the three classical systems that feature in the monument's instruments.<ref name="portal" />]]
[[File:Kapali Yantra.jpg|thumb|Kapali Yantra at Jantar Mantar, Jaipur]]
[[File:Laghu samrat yantra.JPG|thumb|Laghu samrat yantra]]
The observatory consists of nineteen instruments for measuring time, predicting [[eclipse]]s, tracking location of major stars as the [[Earth]] orbits around the Sun, ascertaining the declinations of planets, and determining the celestial altitudes and related ephemerides. The instruments are (alphabetical):<ref name="portal" />

#Chakra Yantra (four 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 four observatories around the world ([[Greenwich]] in [[United Kingdom|UK]], [[Zurich]] in [[Switzerland]], Notke in [[Japan]] and Saitchen in [[Pacific Ocean|Pacific]]); this is equivalent of a wall of clocks registering local times in different parts of the world.)<ref name="kelly1">{{cite book|last1=David Kelly|title=Exploring Ancient Skies: A Survey of Ancient and Cultural Astronomy|date=2011|publisher=Springer|isbn=978-1441976239|page=82}}</ref>
#Dakshin Bhitti Yantra (measures meridian, [[altitude]] and zenith distances of celestial bodies)<ref name="kelly1" />
#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)<ref name="lindsay1">{{cite book|last1=Lindsay Brown|title=Rajasthan, Delhi & Agra|date=2008|isbn=978-1741046908|page=157}}</ref>
#Disha Yantra (used to detect the direction)
#Dhruva Darshak Pattika (observe and find the location of [[pole star]] with respect to other celestial bodies)<ref name="lindsay1" />
#Jai Prakash Yantra (two hemispherical bowl-based sundials with marked marble slabs that map inverted images of sky and allow the observer to move inside the instrument; measures altitudes, azimuths, hour angles, and declinations)<ref name="portal" /><ref name="kelly1" />
#Kapali Yantra (measures coordinates of celestial bodies in azimuth and equatorial systems; any point in the sky can be visually transformed from one coordinate system to another)<ref name="kapala1" />
#Kanali Yantra
#Kranti Vritta Yantra (measures [[longitude]] and [[latitude]] of celestial bodies)
#Laghu Samrat Yantra (the smaller sundial at the monument, inclined at 27 degrees, to measure time, albeit less accurately than Vrihat Samrat Yantra)<ref name="lindsay1" />
#[[Mishra Yantra]] (meaning ''mixed instrument'', it is a compilation of five different instruments)
#Nadi Valaya Yantra (two sundials on different faces of the instrument, the two faces representing the north and south hemispheres; measuring the time to an accuracy of less than a minute)<ref name="lindsay1" />
#Palbha Yantra
#Rama Yantra (an upright building used to find the altitude and the azimuth of [[Sun]])
#Rashi Valaya Yantra (12 gnomon dials that measure ecliptic coordinates of stars, planets and all 12 constellation systems)
#Shastansh Yantra (next to Vrihat Samrat Yantra) This instrument has a 60-degree arc built in the meridian plane within a dark chamber. At noon, the Sun's pinhole image falls on a scale below enabling the observer to measure the zenith distance, declination, and the diameter of the Sun.)<ref>{{cite book|last1=Andreas Volwahsen|title=Cosmic architecture in India|date=2001|publisher=Prestel|isbn=978-3791325064|pages=48–73}}</ref>
#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 allow measurement of the altitude of celestial bodies)<ref name="lindsay1" /> [[File:Unnatamsa Yantra.jpg|thumb|Unnatamsa Yantra]]
#Vrihat Samrat Yantra (world's largest [[gnomon]] sundial, measures time in intervals of 2 seconds using shadow cast from the sunlight)
#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]])<ref>{{cite book|last1=SC Bhatt|title=Land and People of Indian States and Union Territories|date=2006|isbn=978-8178353791|page=362}}</ref> [[File:Yantra Raj.jpg|thumb|Yantra Raj]]

The Vrihat Samrat Yantra, which means the "great king of instruments", is {{convert|88|ft|m}} high, making it one of the world's largest [[sundial]]s.<ref>{{cite news|title=Largest sundial world record|url=http://www.heraldo.es/noticias/aragon/zaragoza_provincia/zaragoza/2013/10/01/el_gigante_del_tiempo_vadorrey_guinness_world_record_251195_301.html}}</ref> Its face is angled at 27 degrees, the latitude of Jaipur. It is purported to tell the time to an accuracy of about two seconds in Jaipur [[time zone|local time]].<ref>{{cite web |url=http://www.jantarmantar.org/Architecture_Science_web.pdf |title=Architecture in the Service of Science: The Astronomical Observatories of Jai Singh II |author=Barry Perlus |publisher=Jantarmantar.org |access-date=11 November 2012 |archive-date=5 February 2009 |archive-url=https://web.archive.org/web/20090205014353/http://jantarmantar.org/Architecture_Science_web.pdf |url-status=dead }}</ref> Its shadow moves visibly at 1&nbsp;mm per second, or roughly a hand's breadth (6&nbsp;cm) every minute. The Hindu chhatri (small cupola) on top is used as a platform for announcing eclipses and the arrival of monsoons.

[[File:JaiPrakashYantraJaipur20080213-3.jpg|thumb|''Jai Prakash Yantra'' at Jantar Mantar, Jaipur]]

The instruments are 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&nbsp;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 the construction of this scale, and subsidence of the foundations has subsequently misaligned them.

===Materials of construction===
[[File:Jantar Mantar in Jaipur giant sundial.jpg|thumb|right|Observation deck of the ''vrihat samrat yantra'' (the world's largest sundial)]]
Built from local stone and marble, each instrument carries an astronomical scale, generally marked on the marble inner lining. Bronze tablets, [[Brick|bricks]] and mortar were also employed in building the instruments in the monument spread over about 18,700 square metres.<ref name="portal" /> It was in continuous use until about 1800, then fell in disuse and disrepair.<ref name="portal" /> Restored again several times during the [[British Empire]], particularly in 1902, the Jantar Mantar was declared a national monument in 1948. It was restored in 2006.<ref name="portal" /> The restoration process in early 20th century replaced some of the original materials of construction with different materials.<ref name="portal" />

Jantar Mantar is managed under the Archeological Sites and Monuments Act of [[Rajasthan]] since 1961, and protected as a National Monument of Rajasthan since 1968.<ref>[http://museumsrajasthan.gov.in/pdf/rules.pdf THE RAJASTHAN MONUMENTS ARCHAEOLOGICAL SITES AND ANTIQUITIES RULES, 1968]</ref>

== Theory ==
The [[Vedas]] mention astronomical terms, measurement of time and calendar, but do not mention any astronomical instruments.<ref name=ohashi1/> The earliest discussion of astronomical instruments, [[gnomon]] and [[Water clock|clepsydra]], is found in the [[Vedanga]]s, ancient Sanskrit texts.<ref name=ohashi1/><ref name=pingree>{{cite book|last1=David Edwin Pingree|title=A History of Indian Literature, Vol 6|date=1981|publisher=[[Otto Harrassowitz Verlag]]|isbn=978-3447021654|pages=52–54}}</ref> The gnomon (called Śaṅku, शङ्कु)<ref name="SpokenSanskrit"/>{{rp|at=gnomon}} found at Jantar Mantar monument is discussed in these first millennium [[Common Era|BCE]] Vedangas and in many later texts such as the [[Kātyāyana]] [[Shulba Sutras]].<ref name=ohashi1/> Other discussions of astronomical instruments are found in Hinduism texts such as the fourth century BCE<ref name=pingree/> [[Arthashastra]], [[Buddhists|Buddhist]] texts such as Sardulakarna-avadana, and [[Jainism]] texts such as [[Surya]]-[[Prajñaptivāda|prajnapti]]. The theories behind the instruments are found in texts by the fifth century CE [[Aryabhata]], sixth century CE [[Brahmagupta]] and [[Varāhamihira]], ninth century [[Lalla]], eleventh century [[Śrīpati]] and [[Bhāskara II]]. The texts of Bhaskara have dedicated chapters on instruments and he calls them ''Yantra-adhyaya''.<ref name=ohashi1/><ref name=pingree/>

The theory of chakra-yantra, yasti-yantra, dhanur-yantra, kapala-yantra, nadivalaya-yantra, kartari-yantra, and others are found in the ancient texts.<ref name=ohashi1/>

== Astronomical Use ==
The full extent of how Jai Singh's instruments were used for astronomical observation remains unclear. While the instruments themselves were impressive, there is limited evidence of a dedicated observational program or a team of trained [[Astronomer|astronomers]]. This raises the question of whether the observatory's primary purpose was purely scientific or also served other symbolic or cultural functions.

The ''Zij Muhammad-Shahi'', an astronomical handbook compiled under Jai Singh's patronage, does not appear to rely heavily on data collected from his observatories. Instead, it primarily utilizes existing tables from sources like the ''[[Ulugh Beg]]'' and ''[[Philippe de La Hire|Philippe de la Hire]]'s astronomical tables''. The ''Zij Muhammad-Shahi'' essentially adapts these tables by incorporating adjustments for the precession of the [[Equinox|equinoxes]] and the difference in longitude between [[Paris]] and [[Delhi]].<ref>{{Cite journal |last=Yavari Ayin |first=Mostafa |year=2023 |title=Defenseless eyes against the sky. A narrative of some astronomical observations before the invention of the telescope |journal=Nojum Magazine [Iranian Magazine of Astronomy] |volume=32 |issue=04 |pages=36–41}}</ref>

==Filming location==
It was used as a filming location for the 2006 film ''[[The Fall (2006 film)|The Fall]]'' as a [[maze]].

[[Storm Thorgerson]] photographed the sundial for the cover of [[Shpongle]]'s DVD, ''Live at the Roundhouse 2008''.<ref>{{cite web |url=http://www.twistedmusic.com/news/news_shpongle_live_in_concert_twsdvd002/ |title=Twisted Music |publisher=Twisted Music |date=23 October 2009 |access-date=11 November 2012 |url-status=dead |archive-url=https://web.archive.org/web/20120220113633/http://www.twistedmusic.com/news/news_shpongle_live_in_concert_twsdvd002/ |archive-date=20 February 2012 |df=dmy-all }}</ref>

It was photographed by [[Julio Cortázar]] with the collaboration of Antonio Gálvez for the book ''[[Prosa del Observatorio]]'' (Editorial Lumen: Barcelona, 1972).

==See also==
; General 
* [[Jantar Mantar]]
* [[Yantra]]
* [[Mantra]]
* [[Tantra]]
* [[Gyarah Sidhi]]
* [[Lists of Intangible Cultural Heritage elements]]

; Research stations
* [[Indian Antarctic Programme]]
* [[Bharati (research station)]] 
* [[Dakshin Gangotri]] First Indian station 1983, converted to support base
* [[Maitri (research station)|Maitri]] Second Indian station 1989
* [[Defence Research and Development Organisation]] 
* [[Defence Institute of High Altitude Research]]
* [[Indian Astronomical Observatory]]
* [[National Centre for Polar and Ocean Research]]
* [[Siachen Base Camp (India)]]
* [[Research stations in Antarctica#List of research stations|List of research stations]]
* [[Antarctic field camps|List of Antarctic field camps]]
* [[List of astronomical observatories]]
* [[List of highest astronomical observatories]]

==References==
{{Reflist}}

==Further reading==
* Sharma, Virendra Nath and Aditya Sharma (1995). ''[https://books.google.com/books?id=QRA2mgZnXXMC Sawai Jai Singh and his astronomy]''. Motilal Banarsidass Publishers Pvt. Ltd. {{ISBN|81-208-1256-5}}.

==External links==
{{Commons category|Jantar Mantar (Jaipur)}}
*[http://museumsrajasthan.gov.in/mounment_Jantar-Mantar.htm Official website of Rajasthan government, India], Jantar Mantar
*[https://web.archive.org/web/20161220201045/http://www.math.nus.edu.sg/aslaksen/gem-projects/hm/0203-1-07-jantar_mantar.pdf Jantar Mantar - Section III] Theory, Construction and Limitations, National University of Singapore
*[https://web.archive.org/web/20161104173817/http://www.panoramio.com/user/4942042/tags/Jantar%20mantar%20jaipur Photos of Jantar Mantar]
*[https://web.archive.org/web/20151210085654/http://www.bomhard.de/englisch/jaipur/00.html Jantar Mantar (Jaipur)]
*[http://www.jantarmantar.org Jantar Mantar] Articles and History
*[http://www.jantarmantar.org/Architecture_Science_web.pdf Architecture in the Service of Science] {{Webarchive|url=https://web.archive.org/web/20090205014353/http://jantarmantar.org/Architecture_Science_web.pdf |date=5 February 2009 }}
*[https://www3.astronomicalheritage.net/index.php/show-entity?idunescowhc=1338 The Jantar Mantar at Jaipur, India] at {{URL|www3.astronomicalheritage.net}}
*{{OpenStreetMap link|n|542886857}}

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{{Indian mathematics}}
{{Indian astronomy}}
{{Telescopes and Observatories in India}}
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[[Category:Tourist attractions in Jaipur]]
[[Category:World Heritage Sites in India]]
[[Category:History of science and technology in India]]
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[[Category:Astronomical observatories in India]]
[[Category:Buildings and structures in Jaipur]]