View source for Indian astronomy

{{Short description|Astronomy on the Indian subcontinent}}
{{EngvarB|date=March 2015}}
{{Use dmy dates|date=September 2021}}
{{Science and technology in India}}

[[Astronomy]] has a long history in the [[Indian subcontinent]], stretching from [[History of India|pre-historic]] to [[History of India (1947–present)|modern times]]. Some of the earliest roots of Indian astronomy can be dated to the period of [[Indus Valley civilisation]] or earlier.<ref name=question>{{cite book |title=A Question and Answer Guide to Astronomy |page=197 |author1=Pierre-Yves Bely |author2=Carol Christian |author3=Jean-René Roy |url=https://books.google.com/books?id=PbLPel3zRdEC&q=%22Indian+astronomy%22&pg=PA197 |publisher=Cambridge University Press |isbn=9780521180665 |date=2010}}</ref><ref name=wiley>{{cite journal |title=Astronomy in the Indus Valley Civilization A Survey of the Problems and Possibilities of the Ancient Indian Astronomy and Cosmology in the Light of Indus Script Decipherment by the Finnish Scholars |doi=10.1111/j.1600-0498.1977.tb00351.x |volume=21 |issue=2 |journal=Centaurus |pages=149–193 |bibcode=1977Cent...21..149A |year=1977 |last1=Ashfaque |first1=Syed Mohammad |doi-access=free}}</ref> Astronomy later developed as a discipline of [[Vedanga]], or one of the "auxiliary disciplines" associated with the study of the [[Veda]]s{{sfn|Sarma|2008a}} dating 1500 BCE or older.<ref>The Vedas: An Introduction to Hinduism's Sacred Texts, Roshen Dalal, p. 188</ref> The oldest known text is the ''[[Vedanga Jyotisha]]'', dated to 1400–1200&nbsp;BCE (with the extant form possibly from 700 to 600 BCE).<ref name=Cosmic>{{cite book |last=Subbarayappa |first=B. V. |editor=Biswas, S. K. |editor2=Mallik, D. C. V. |editor3=Vishveshwara, C. V. |editor3-link=C. V. Vishveshwara |title=Cosmic Perspectives |chapter-url=https://books.google.com/books?id=PFTGKi8fjvoC&pg=FA25 |date=14 September 1989 |publisher=Cambridge University Press |isbn=978-0-521-34354-1 |pages=25–40 |chapter=Indian astronomy: An historical perspective}}</ref>

Indian astronomy was influenced by [[Greek astronomy]] beginning in the 4th century&nbsp;BCE<ref name="Andersen">Highlights of Astronomy, Volume 11B: As presented at the XXIIIrd General Assembly of the IAU, 1997. Johannes Andersen Springer, 31 January 1999 – Science – 616 pages. p. 721 [https://books.google.com/books?id=gQYscrT0fgQC&dq=yavanajataka&pg=PA721]</ref><ref name="Leverington">Babylon to Voyager and Beyond: A History of Planetary Astronomy. David Leverington. Cambridge University Press, 29 May 2010 – Science – 568 pages. p. 41 [https://books.google.com/books?id=6Hpi202ybn8C&dq=greek+astronomy+india&pg=PA41]</ref><ref name="Evans">The History and Practice of Ancient Astronomy. James Evans. Oxford University Press, 1 October 1998 – History – 496 pages. p.?393 [https://books.google.com/books?id=LVp_gkwyvC8C&dq=greek+astronomy+india&pg=PA393]</ref> and through the early centuries of the Common Era, for example by the [[Yavanajataka]]<ref name="Andersen"/> and the ''[[Romaka Siddhanta]]'', a Sanskrit translation of a Greek text disseminated from the 2nd century.<ref name="Naskar">Foreign Impact on Indian Life and Culture (c. 326 B.C. to c. 300 A.D.). Satyendra Nath Naskar.  Abhinav Publications, 1 January 1996 – History – 253 pages. pp. 56–57 [https://books.google.com/books?id=SuEBGgRHHuIC&dq=greek+astronomy+india&pg=PA57]</ref>

Indian astronomy flowered in the 5th–6th century, with [[Aryabhata]], whose work, ''[[Aryabhatiya]],'' represented the pinnacle of astronomical knowledge at the time. The Aryabhatiya is composed of four sections, covering topics such as units of time, methods for determining the positions of planets, the cause of day and night, and several other cosmological concepts.<ref>{{Cite book |last=Clark |first=Walter |title=Aryabhatiya: An Ancient Indian Work on Mathematics and Astronomy – An English Translation |publisher=The University of Chicago Press |year=1930}}</ref> Later, Indian astronomy significantly influenced [[Muslim astronomy]], [[Chinese astronomy]], European astronomy and others.<ref>"Star Maps: History, Artistry, and Cartography", p. 17, by Nick Kanas, 2012</ref> Other astronomers of the classical era who further elaborated on Aryabhata's work include [[Brahmagupta]], [[Varahamihira]] and [[Lalla]].

An identifiable native Indian astronomical tradition remained active throughout the medieval period and into the 16th or 17th century, especially within the [[Kerala school of astronomy and mathematics]].

==History==
{{Multiple images|direction=vertical|image1=2064 aryabhata-crp.jpg|image2=Jantar Mantar Delhi 27-05-2005.jpg|image3=1st verse of the 1st chapter of the Surya Siddhanta Hindu astronomy, 1847 Sanskrit manuscript edition.jpg|caption1=[[Aryabhata]], Indian mathematician and astronomer |caption2=[[Jantar Mantar]], astronomical observatory made by Raja Jai Singh |caption3=''[[Surya Siddhanta]]'', an astronomical treatise}}

Some of the earliest forms of astronomy can be dated to the [[Indus Valley Civilisation]] or earlier.<ref name=question/><ref name=wiley/> Some cosmological concepts are present in the [[Vedas]], as are notions of the movement of heavenly bodies and the course of the year.{{sfn|Sarma|2008a}} The Rig Veda is one of the oldest pieces of Indian literature. Rig Veda 1-64-11 & 48 describes time as a wheel with 12 parts and 360 spokes (days), with a remainder of 5, making reference to the solar calendar.<ref>{{Cite journal |last=Sidharth |first=B. G. |date=1998 |title=The Calendric Astronomy of the Vedas |url=https://articles.adsabs.harvard.edu//full/1998BASI...26..107S/0000108.000.html |journal=Bulletin of the Astronomical Society of India |volume=26 |page=108 |bibcode=1998BASI...26..107S |via=NASA Astrophysics Data System}}</ref> As in other traditions, there is a close association of [[astronomy and religion]] during the early history of the science, astronomical observation being necessitated by spatial and temporal requirements of [[orthopraxy|correct performance]] of religious ritual. Thus, the ''[[Shulba Sutras]]'', texts dedicated to altar construction, discusses advanced mathematics and basic astronomy.<ref name=abraham08/> ''[[Vedanga Jyotisha]]'' is another of the earliest known Indian texts on astronomy,<ref>{{cite book |title=Kalaprakasika |author=N. P. Subramania Iyer |publisher=Asian Educational Services |page=3}}</ref> it includes the details about the Sun, Moon, [[nakshatra]]s, [[lunisolar calendar]].<ref>Ōhashi (1993)</ref><ref>{{cite book |title=Science, Technology, Imperialism, and War |page=33 |author=Jyoti Bhusan Das Gupta |publisher=Pearson Education India}}</ref> The Vedanga Jyotisha describes rules for tracking the motions of the Sun and the Moon for the purposes of ritual. According to the Vedanga Jyotisha, in a ''yuga'' or "era", there are 5 solar years, 67 lunar sidereal cycles, 1,830 days, 1,835 [[sidereal day]]s and 62 [[Synodic month|synodic]] months.<ref>{{Cite journal |last=Kak |first=Shubash |date=1995 |title=The Astronomy of the Age of Geometric Altars |journal=Quarterly Journal of the Royal Astronomical Society |volume=36 |pages=385–395 |bibcode=1995QJRAS..36..385K}}</ref>

Greek astronomical ideas began to enter India in the 4th century BCE following the [[Indian campaign of Alexander the Great|conquests of Alexander the Great]].<ref name="Andersen"/><ref name="Leverington"/><ref name="Evans"/><ref name="Naskar"/> By the early centuries of the Common Era, [[Indo-Greek Kingdom|Indo-Greek]] influence on the astronomical tradition is visible, with texts such as the [[Yavanajataka]]<ref name="Andersen"/> and ''[[Romaka Siddhanta]]''.<ref name="Naskar"/> 
Later astronomers mention the existence of various [[siddhanta]]s during this period, among them a text known as the 
''[[Surya Siddhanta]]''. These were not fixed texts but rather an oral tradition of knowledge, and their content is not extant. The text today known as ''Surya Siddhanta'' dates to the [[Gupta period]] and was received by [[Aryabhata]].

The classical era of Indian astronomy begins in the late Gupta era, in the 5th to 6th centuries. 
The ''[[Pancha-Siddhantika|Pañcasiddhāntikā]]'' by [[Varāhamihira]] (505 CE) approximates the method for determination of the meridian direction from any three positions of the shadow using a [[gnomon]].<ref name=abraham08/> By the time of [[Aryabhata]] the motion of planets was treated to be elliptical rather than circular.<ref name=Hayashi08Aryabhata>Hayashi (2008), ''Aryabhata I''</ref> Other topics included definitions of different units of time, [[eccentricity (mathematics)|eccentric]] models of planetary motion, [[epicycle|epicyclic]] models of planetary motion, and planetary longitude corrections for various terrestrial locations.<ref name=Hayashi08Aryabhata/>
[[File:Hindu calendar 1871-72.jpg|right|upright=1.15|thumb|A page from the Hindu calendar 1871–1872.]]

==Calendars==

{{Further|Hindu calendar}}{{See also|Astronomical basis of the Hindu calendar}}
The divisions of the year were on the basis of religious rites and seasons (''[[Ṛtú]]'').<ref name=van_Buitenen08>J.A.B. van Buitenen (2008)</ref> The duration from mid March–mid May was taken to be spring (''[[Vasanta (season)|vasanta]]''), mid May–mid July: summer (''[[grishma]]''), mid July–mid September: rains (''[[Varsha (season)|varsha]]''), mid September–mid November: autumn (''[[Sharada (season)|sharada]]''), mid November–mid January: winter (''[[Hemanta (season)|hemanta]]''), mid January–mid March: the dews (''[[Shishira (season)|shishira]]'').<ref name=van_Buitenen08/>

In the ''{{IAST|Vedānga Jyotiṣa}}'', the year begins with the winter solstice.<ref>Bryant (2001), 253</ref> Hindu calendars have several [[calendar era|eras]]:

* The [[Hindu calendar]], counting from the start of the [[Kali Yuga]], has its epoch on 18 February 3102&nbsp;BCE Julian (23 January 3102&nbsp;BCE Gregorian).
* The [[Vikram Samvat]] calendar, introduced about the 12th century, counts from 56 to 57 BCE.
* The "[[Saka|Saka Era]]", used in some [[Hindu calendar]]s and in the [[Indian national calendar]], has its epoch near the vernal equinox of year 78.
* The [[Saptarishi]] calendar traditionally has its epoch at 3076 BCE.<ref>See A. Cunningham (1883), ''A Book of Indian Eras''.</ref>

J. A. B. van Buitenen (2008) reports on the [[calendar]]s in India:

{{Blockquote|1=The oldest system, in many respects the basis of the classical one, is known from texts of about 1000 BCE. It divides an approximate solar year of 360 days into 12 lunar months of 27 (according to the early Vedic text {{IAST|Taittirīya Saṃhitā}} 4.4.10.1–3) or 28 (according to the ''[[Atharvaveda]]'', the fourth of the Vedas, 19.7.1.) days. The resulting discrepancy was resolved by the intercalation of a leap month every 60 months. Time was reckoned by the position marked off in constellations on the ecliptic in which the Moon rises daily in the course of one lunation (the period from [[New Moon]] to New Moon) and the Sun rises monthly in the course of one year. These [[constellations]] ({{IAST|nakṣatra}}) each measure an arc of 13° 20{{prime}} of the ecliptic circle. The positions of the Moon were directly observable, and those of the Sun inferred from the Moon's position at Full Moon, when the Sun is on the opposite side of the Moon. The position of the Sun at midnight was calculated from the {{IAST|nakṣatra}} that culminated on the meridian at that time, the Sun then being in opposition to that {{IAST|nakṣatra}}.<ref name=van_Buitenen08/>}}

==Astronomers==
*'''[[Vedanga Jyotisha|Lagadha]] (1st millennium BCE)''': The earliest astronomical text{{snd}}named ''[[Vedanga Jyotisha|{{IAST|Vedānga Jyotiṣa}}]]'' details several astronomical attributes generally applied for timing social and religious events.<ref name= Subbaarayappa/> The ''{{IAST|Vedānga Jyotiṣa}}'' also details astronomical calculations, calendrical studies, and establishes rules for empirical observation.<ref name= Subbaarayappa>Subbaarayappa (1989)</ref> Since the texts written by 1200 BCE were largely religious compositions the ''{{IAST|Vedānga Jyotiṣa}}'' has connections with [[Indian astrology]] and details several important aspects of the time and seasons, including lunar months, solar months, and their adjustment by a lunar leap month of ''Adhimāsa''.<ref name=Tripathi08>Tripathi (2008)</ref> ''[[Ritu (Indian season)|Ṛtú]]s'' are also described as ''[[yugāṃśa]]s'' (or parts of the ''[[yuga]]'', i.e. conjunction cycle).<ref name=Tripathi08/> Tripathi (2008) holds that 'Twenty-seven constellations, eclipses, seven planets, and twelve signs of the zodiac were also known at that time.'<ref name=Tripathi08/>
*'''[[Aryabhata|Āryabhaṭa]] (476–550 CE)''': Āryabhaṭa was the author of the ''[[Aryabhatiya|Āryabhatīya]]'' and the ''Āryabhaṭasiddhānta'', which, according to Hayashi (2008), "circulated mainly in the northwest of India and, through the [[Sasanian dynasty]] (224–651) of [[Iran]], had a profound influence on the development of [[Islamic astronomy]]. Its contents are preserved to some extent in the works of Varāhamihira (flourished c. 550), Bhāskara I (flourished c. 629), Brahmagupta (598{{snd}}c. 665), and others. It is one of the earliest astronomical works to assign the start of each day to midnight."<ref name="Hayashi08Aryabhata"/> Aryabhata explicitly mentioned that the Earth rotates about its axis, thereby causing what appears to be an apparent westward motion of the stars.<ref name=Hayashi08Aryabhata/> In his book, Aryabhata, he suggested that the Earth was sphere, containing a circumference of 24,835 miles (39,967&nbsp;km).<ref>Indian Astronomy. (2013). In D. Leverington, ''Encyclopedia of the history of Astronomy and Astrophysics''. Cambridge, United Kingdom: Cambridge University Press. Retrieved from http://search.credoreference.com/content/entry/cupaaa/indian_astronomy/0</ref>  Aryabhata also mentioned that reflected sunlight is the cause behind the shining of the Moon.<ref name=Hayashi08Aryabhata/> Aryabhata's followers were particularly strong in [[South India]], where his principles of the diurnal rotation of the Earth, among others, were followed and a number of secondary works were based on them.{{sfn|Sarma|2008a}}
*'''[[Brahmagupta]] (598–668 CE)''': ''[[Brāhmasphuṭasiddhānta]]'' (Correctly Established Doctrine of Brahma, 628 CE) dealt with both [[Indian mathematics]] and astronomy. Hayashi (2008) writes: "It was translated into Arabic in Baghdad about 771 and had a major impact on [[Islamic mathematics]] and astronomy".<ref name=Hayashi08-Brhgupt>Hayashi (2008), Brahmagupta</ref> In ''Khandakhadyaka'' (A Piece Eatable, 665 CE) Brahmagupta reinforced Aryabhata's idea of another day beginning at midnight.<ref name=Hayashi08-Brhgupt/> ''Brahmagupta'' also calculated the instantaneous motion of a planet, gave correct equations for [[parallax]], and some information related to the computation of eclipses.{{sfn|Sarma|2008a}} His works introduced the Indian concept of mathematics based astronomy into the [[Arab world]].{{sfn|Sarma|2008a}} He also theorized that all bodies with mass are [[Gravity|attracted]] to the Earth.<ref>Brahmagupta, ''Brahmasphutasiddhanta'' (628) ([[cf.]] [[Al-Biruni]] (1030), ''Indica'')</ref>
*'''[[Varahamihira|Varāhamihira]] (505 CE)''': Varāhamihira was an astronomer and mathematician who studied and Indian astronomy as well as the many principles of Greek, Egyptian, and Roman astronomical sciences.<ref name=Vhmr/> His ''Pañcasiddhāntikā '' is a treatise and compendium drawing from several knowledge systems.<ref name=Vhmr>''Varāhamihira''. ''Encyclopædia Britannica'' (2008)</ref>
*'''[[Bhaskara I|Bhāskara I]] (629 CE)''': Authored the astronomical works ''Mahābhāskariya'' (Great Book of Bhāskara), ''Laghubhaskariya'' (Small Book of Bhaskara), and the ''Aryabhatiyabhashya'' (629 CE){{snd}}a commentary on the ''Āryabhatīya'' written by Aryabhata.<ref name=Hayashi08-BhI/> Hayashi (2008) writes 'Planetary longitudes, [[heliacal rising]] and setting of the planets, conjunctions among the planets and stars, solar and lunar eclipses, and the [[Lunar phase|phases of the Moon]] are among the topics Bhāskara discusses in his astronomical treatises.'<ref name=Hayashi08-BhI>Hayashi (2008), ''Bhaskara I''</ref> Bhāskara I's works were followed by Vateśvara (880 CE), who in his eight chapter ''Vateśvarasiddhānta'' devised methods for determining the parallax in longitude directly, the motion of the [[equinox]]es and the [[solstice]]s, and the quadrant of the Sun at any given time.{{sfn|Sarma|2008a}}
*'''[[Lalla]] (8th century CE)''': Author of the ''Śiṣyadhīvṛddhida'' (Treatise Which Expands the Intellect of Students), which corrects several assumptions of Āryabhaṭa.<ref name=Sarma08-Lalla/> The ''Śisyadhīvrddhida'' of Lalla itself is divided into two parts: ''Grahādhyāya'' and ''Golādhyāya''.<ref name=Sarma08-Lalla/> ''Grahādhyāya'' (Chapter I-XIII) deals with planetary calculations, determination of the mean and true planets, three problems pertaining to diurnal motion of Earth, eclipses, rising and setting of the planets, the various cusps of the Moon, planetary and astral conjunctions, and complementary situations of the Sun and the Moon.<ref name=Sarma08-Lalla>Sarma (2008), ''Lalla''</ref> The second part{{snd}}titled ''Golādhyāya'' (chapter XIV–XXII){{snd}}deals with graphical representation of planetary motion, astronomical instruments, spherics, and emphasizes on corrections and rejection of flawed principles.<ref name=Sarma08-Lalla/> Lalla shows influence of Āryabhata, Brahmagupta, and Bhāskara I.<ref name=Sarma08-Lalla/> His works were followed by later astronomers Śrīpati, Vateśvara, and [[Bhāskara II|Bhāskara]] II.<ref name=Sarma08-Lalla/> Lalla also authored the ''Siddhāntatilaka''.<ref name=Sarma08-Lalla/>
*'''[[Śatānanda]] (1068–1099 CE)''': Authored ''Bhāsvatī'' (1099) – estimated [[precession]]<ref>{{cite journal |author=Panda, Sudhira |year=2019 |title=The Bhāsvatī astronomical handbook of Śatānanda |url=http://cdsads.u-strasbg.fr/pdf/2019JAHH...22..536P |journal=Journal of Astronomical History and Heritage |volume=22 |issue=3 |pages=536–544 |doi=10.3724/SP.J.1440-2807.2019.03.12 |s2cid=256574558}}</ref>
*'''[[Bhāskara II]] (1114 CE)''': Authored ''[[Siddhānta Shiromani|{{IAST|Siddhāntaśiromaṇi}}]]'' (Head Jewel of Accuracy) and ''{{IAST|[[Karaṇakutūhala]]}}'' (Calculation of Astronomical Wonders) and reported on his observations of planetary positions, conjunctions, eclipses, [[cosmography]], geography, mathematics, and astronomical equipment used in his research at the [[observatory]] in [[Ujjain]], which he headed<ref name=Hayashi08-BhII>Hayashi (2008), ''Bhaskara II''</ref>
*'''[[Shripati|Śrīpati]] (1045 CE)''': Śrīpati was an astronomer and mathematician who followed the Brahmagupta school and authored the ''Siddhāntaśekhara'' (The Crest of Established Doctrines) in 20 chapters, thereby introducing several new concepts, including Moon's second [[Evection|inequality]].{{sfn|Sarma|2008a}}<ref name=Hayashi-Shripati>Hayashi (2008), ''Shripati''</ref>
*'''[[Mahendra Sūri]] (14th century CE)''': Mahendra Sūri authored the ''Yantra-rāja'' (The King of Instruments, written in 1370 CE){{snd}}a Sanskrit work on the [[astrolabe]], itself introduced in India during the reign of the 14th century [[Tughlaq dynasty]] ruler [[Firuz Shah Tughlaq]] (1351–1388 CE).<ref name=Ohashi1997-Astrolabe/> Sūri seems to have been a [[Jain]] astronomer in the service of Firuz Shah Tughluq.<ref name=Ohashi1997-Astrolabe/> The 182 verse ''Yantra-rāja'' mentions the astrolabe from the first chapter onwards, and also presents a fundamental formula along with a numerical table for drawing an astrolabe although the proof itself has not been detailed.<ref name=Ohashi1997-Astrolabe/> Longitudes of 32 stars as well as their latitudes have also been mentioned.<ref name=Ohashi1997-Astrolabe/> Mahendra Sūri also explained the [[Gnomon]], [[Equatorial coordinate system|equatorial co-ordinates]], and [[Elliptic coordinate system|elliptical co-ordinates]].<ref name=Ohashi1997-Astrolabe/> The works of Mahendra Sūri may have influenced later astronomers like Padmanābha (1423 CE){{snd}}author of the ''Yantra-rāja-adhikāra'', the first chapter of his ''Yantra-kirṇāvali''.<ref name=Ohashi1997-Astrolabe>Ōhashi (1997)</ref>
*'''[[Makaranda]]carya (1438–1478 CE)''': Author of the ''Makaranda sāriṇī''
*'''[[Parameshvara Nambudiri]] (1380–1460 CE)''': Creator of the ''Drgganita'' or [[Drig system]], Parameshvara belonged to the [[Kerala school of astronomy and mathematics]]. Parameshvara was a proponent of [[observational astronomy]] in [[medieval India]] and he himself had made a series of [[eclipse]] observations to verify the accuracy of the computational methods then in use. Based on his eclipse observations, Parameshvara proposed several corrections to the astronomical parameters which had been in use since the times of [[Aryabhata]].
*'''[[Nilakantha Somayaji]] (1444–1544 CE)''': In 1500, Nilakantha Somayaji of the [[Kerala school of astronomy and mathematics]], in his ''[[Tantrasangraha]]'', revised Aryabhata's model for the planets [[Mercury (planet)|Mercury]] and [[Venus]]. His equation of the [[Center of mass|centre]] for these planets remained the most accurate until the time of [[Johannes Kepler]] in the 17th century.<ref name=Joseph408>Joseph, 408</ref> Nilakantha Somayaji, in his ''Āryabhaṭīyabhāṣya'', a commentary on Āryabhaṭa's ''Āryabhaṭīya'', developed his own computational system for a partially [[heliocentrism|heliocentric]] planetary model, in which Mercury, Venus, [[Mars]], [[Jupiter]] and [[Saturn]] orbit the [[Sun]], which in turn orbits the [[Earth]], similar to the [[Tychonic system]] later proposed by [[Tycho Brahe]] in the late 16th century. Nilakantha's system, however, was mathematically more efficient than the Tychonic system, due to correctly taking into account the equation of the centre and [[latitude|latitudinal]] motion of Mercury and Venus. Most astronomers of the [[Kerala school of astronomy and mathematics]] who followed him accepted his planetary model.<ref name=Joseph408/><ref>Ramasubramanian etc. (1994)</ref> He also authored a treatise titled ''[[Jyotirmimamsa|Jyotirmīmāṁsā]]'' stressing the necessity and importance of astronomical observations to obtain correct parameters for computations.
*'''[[Daśabala]] ({{floruit}} 1055–1058 CE)''': Author of ''Cintāmanṇisāraṇikā'' (1055) and the ''Karaṇakamalamārtaṇḍa'' (1058).
*'''[[Achyuta Pisharati|Acyuta Piṣāraṭi]] (1550–1621 CE)''': ''Sphuṭanirṇaya'' (Determination of True Planets) details an elliptical correction to existing notions.<ref name=Sarma-A.P./> ''Sphuṭanirṇaya'' was later expanded to ''Rāśigolasphutānīti'' (True Longitude Computation of the Sphere of the Zodiac).<ref name=Sarma-A.P.>Sarma (2008), ''Acyuta Pisarati''</ref> Another work, ''Karanottama'' deals with eclipses, complementary relationship between the Sun and the Moon, and 'the derivation of the mean and true planets'.<ref name=Sarma-A.P./> In ''Uparāgakriyākrama'' (Method of Computing Eclipses), Acyuta Piṣāraṭi suggests improvements in methods of calculation of eclipses.<ref name=Sarma-A.P./>
*'''[[Dinakara]] (1550 CE)''': Author of a popular work, the Candrārkī with 33 verses to produce calendars, calculate lunar, solar, and star positions.<ref>{{cite journal |author=Kolachana, Aditya |author2=Montelle, Clemency |author3=Dhammaloka, J. |author4=Melnad, K. |author5=Mahesh, K. |author6=Vyas, P. |author7=Ramasubramanian, K. |author8=Sriram, M.S. |author9=Pai, V. |year=2018 |title=A Critical Edition of the Candrārkī of Dinakara: A Text Concerning Solar and Lunar Tables |url=https://journals.library.ualberta.ca/hssa/index.php/hssa/article/view/35/90 |journal=History of Science in South Asia |volume=6 |pages=127–161 |doi=10.18732/hssa.v6i0.35 |doi-access=free}}</ref><ref>{{cite journal |author1=Kolachana, A. |author2=Montelle, C. |author3=Dhammaloka, J. |author4=Melnad, K. |author5=Mahesh, K. |author6=Vyas, P. |year=2018 |title=The Candrārkī of Dinakara: A Text Related to Solar and Lunar Tables. |journal=Journal for the History of Astronomy |volume=49 |issue=3 |pages=306–344 |doi=10.1177/0021828618787556 |bibcode=2018JHA....49..306K |s2cid=125563931}}</ref>
*'''[[Mathuranatha Sarman|Mathurānātha Śarman]] (1609 CE)''': Author of ''Ravisiddhāntamañjarī'' or ''Sūryasiddhāntamañjarī''
*'''[[Pathani Samanta]] (1835–1904 )''' the last in chain of naked eye astronomers of India belonging to Siddhantic Era. Was born in Kahndapada, a feudatory state of Odisha. He studied various Siddhantas and found them to be erroneous as the planets were either not found at the right places or at right time. He made more studies, observed deeply and made several instruments to perfect his analysis of his observation. He composed his findings into a voluminous treatise name ''Siddhanta Darpan'' giving new formulaes to predict celestial occurrences. His almanac was adopted by the Jagannath Temple of Puri. He was awarded the title of Mahamahopadhyaya by the Viceroy of India Mr.Lansdowne and also a title ''Harichandan Mahapatra'' by Gajapati King of Puri. The instruments designed by him were for measurement of time and position of stellar bodies and were named Chapa Yantra, Mana Yantra, Golardha Yantra, Dhanu Yantra, Chakra Yantra, Swayambha Yantra, Gola Yantra etc. A postage stamp has been issued by the government of India in his honor.

==Instruments used==
[[File:Jantar Mantar at Jaipur.jpg|thumb|right|[[Jai Singh II|Sawai Jai Singh]] (1688–1743 CE) initiated the construction of several observatories. Shown here is the [[Jantar Mantar (Jaipur)]] observatory.]]
[[File:Jantar Delhi.jpg|thumb|right|[[Yantra Mandir]] (completed by 1743 CE), [[Delhi]].]]
[[File:Grad-Scale-Hindu-Arabic-numerals.jpg|right|thumb|Astronomical instrument with graduated scale and notation in [[Hindu-Arabic numerals]].]]
Among the devices used for astronomy was [[gnomon]], known as ''Sanku'', in which the shadow of a vertical rod is applied on a horizontal plane in order to ascertain the cardinal directions, the latitude of the point of observation, and the time of observation.<ref name=Ohashiast-inst>Ōhashi (2008), ''Astronomical Instruments in India''</ref> This device finds mention in the works of Varāhamihira, Āryabhata, Bhāskara, Brahmagupta, among others.<ref name=abraham08>Abraham (2008)</ref> The [[Cross-staff]], known as ''Yasti-yantra'', was used by the time of [[Bhaskara II]] (1114–1185 CE).<ref name=Ohashiast-inst/> This device could vary from a simple stick to V-shaped staffs designed specifically for determining angles with the help of a calibrated scale.<ref name=Ohashiast-inst/> The [[Water clock|clepsydra]] (''Ghatī-yantra'') was used in India for astronomical purposes until recent times.<ref name=Ohashiast-inst/> Ōhashi (2008) notes that: "Several astronomers also described water-driven instruments such as the model of fighting sheep."<ref name=Ohashiast-inst/>

The [[armillary sphere]] was used for observation in India since early times, and finds mention in the works of Āryabhata (476 CE).<ref name=Sarma08>Sarma (2008), ''Armillary Spheres in India''</ref> The ''Goladīpikā''{{snd}}a detailed treatise dealing with globes and the armillary sphere was composed between 1380 and 1460 CE by [[Parameśvara]].<ref name=Sarma08/> On the subject of the usage of the armillary sphere in India, Ōhashi (2008) writes: "The Indian armillary sphere (''gola-yantra'') was based on equatorial coordinates, unlike the Greek armillary sphere, which was based on ecliptical coordinates, although the Indian armillary sphere also had an ecliptical hoop. Probably, the celestial coordinates of the junction stars of the lunar mansions were determined by the armillary sphere since the seventh century or so. There was also a celestial globe rotated by flowing water."<ref name=Ohashiast-inst/>

An instrument invented by the mathematician and astronomer Bhaskara II (1114–1185 CE) consisted of a rectangular board with a pin and an index arm.<ref name=Ohashiast-inst/> This device{{snd}}called the ''Phalaka-yantra''{{snd}}was used to determine time from the Sun's altitude.<ref name=Ohashiast-inst/> The ''Kapālayantra'' was an [[equatorial sundial]] instrument used to determine the Sun's [[azimuth]].<ref name=Ohashiast-inst/> ''Kartarī-yantra'' combined two semicircular board instruments to give rise to a 'scissors instrument'.<ref name=Ohashiast-inst/> Introduced from the Islamic world and first finding mention in the works of [[Mahendra Suri]]{{snd}}the court astronomer of [[Firuz Shah Tughluq]] (1309–1388 CE){{snd}}the [[astrolabe]] was further mentioned by Padmanābha (1423 CE) and Rāmacandra (1428 CE) as its use grew in India.<ref name=Ohashiast-inst/>

Invented by ''Padmanābha'', a nocturnal polar rotation instrument consisted of a rectangular board with a slit and a set of pointers with concentric graduated circles.<ref name=Ohashiast-inst/> Time and other astronomical quantities could be calculated by adjusting the slit to the directions of α and β [[Ursa Minor]].<ref name=Ohashiast-inst/> Ōhashi (2008) further explains that: "Its backside was made as a quadrant with a plumb and an index arm. Thirty parallel lines were drawn inside the quadrant, and trigonometrical calculations were done graphically. After determining the sun's altitude with the help of the plumb, time was calculated graphically with the help of the index arm."<ref name=Ohashiast-inst/>

Ōhashi (2008) reports on the observatories constructed by [[Jai Singh II of Amber]]:

{{Blockquote|1=The Mahārāja of Jaipur, [[Jai Singh II|Sawai Jai Singh]] (1688–1743 CE), constructed five astronomical observatories at the beginning of the eighteenth century. The observatory in [[Mathura, Uttar Pradesh|Mathura]] is not extant, but those in Delhi, [[Jaipur]], [[Ujjain]], and [[Banaras]] are. There are several huge instruments based on Hindu and Islamic astronomy. For example, the samrāt.-yantra (emperor instrument) is a huge sundial which consists of a triangular gnomon wall and a pair of quadrants toward the east and west of the gnomon wall. Time has been graduated on the quadrants.<ref name=Ohashiast-inst/>}}

The seamless [[celestial globe]] invented in [[Mughal India]], specifically [[Lahore]] and [[Kashmir]], is considered to be one of the most impressive astronomical instruments and remarkable feats in [[metallurgy]] and engineering. All [[globe]]s before and after this were seamed, and in the 20th century, it was believed by metallurgists to be technically impossible to create a metal globe without any [[wiktionary:seam|seams]], even with modern technology. It was in the 1980s, however, that [[Emilie Savage-Smith]] discovered several celestial globes without any seams in Lahore and Kashmir. The earliest was invented in Kashmir by Ali Kashmiri ibn Luqman in 1589–90 CE during [[Akbar the Great]]'s reign; another was produced in 1659–60 CE by Muhammad Salih Tahtawi with Arabic and Sanskrit inscriptions; and the last was produced in Lahore by a Hindu metallurgist Lala Balhumal Lahuri in 1842 during [[Jagatjit Singh Bahadur]]'s reign. 21 such globes were produced, and these remain the only examples of seamless metal globes. These Mughal metallurgists developed the method of [[lost-wax casting]] in order to produce these globes.<ref>Savage-Smith (1985)</ref>

==International discourse==
[[File:AiKhanoumSunDial.jpg|thumb|upright=0.95|Greek equatorial [[sun dial]], [[Ai-Khanoum]], Afghanistan 3rd–2nd centuries&nbsp;BCE]]

===Indian and Greek astronomy===
According to [[David Pingree]], there are a number of Indian astronomical texts dated to the sixth century CE or later with a high degree of certainty. There is substantial similarity between these and pre-Ptolemaic Greek astronomy.<ref name = "Pingree (1976)">{{cite journal |first=David |last=Pingree |title=The Recovery of early Greek Astronomy from India |publisher=Science History Publications Ltd. |journal=Journal for the History of Astronomy |volume=7 |issue=19 |date=1976 |pages=109–123 |bibcode=1976JHA.....7..109P |doi=10.1177/002182867600700202 |s2cid=68858864}}</ref> Pingree believes that these similarities suggest a Greek origin for certain aspects of Indian astronomy. One of the direct proofs for this approach is the fact quoted that many Sanskrit words related to astronomy, astrology and calendar are either direct phonetic borrowings from the Greek language, or translations, assuming complex ideas, like the names of the days of the week which presuppose a relation between those days, planets (including Sun and Moon) and gods.{{Citation needed|date=March 2022}}

With the rise of [[Hellenistic period|Greek culture in the east]], [[Greek astronomy#Hellenistic astronomy|Hellenistic astronomy]] filtered eastwards to India, where it profoundly influenced the local astronomical tradition.<ref name="Andersen"/><ref name="Leverington"/><ref name="Evans"/><ref name="Naskar"/><ref name="Pingree (1978), 533, 554f."/> For example, [[Hellenistic civilization|Hellenistic]] astronomy is known to have been practised near India in the [[Greco-Bactrian Kingdom|Greco-Bactrian]] city of [[Ai-Khanoum]] from the 3rd century BCE. Various sun-dials, including an equatorial sundial adjusted to the latitude of [[Ujjain]] have been found in archaeological excavations there.<ref>Pierre Cambon, Jean-François Jarrige. "Afghanistan, les trésors retrouvés: Collections du Musée national de Kaboul". Éditions de la Réunion des musées nationaux, 2006 – 297 pages. p. 269 [https://books.google.com/books?id=xJFtQgAACAAJ&q=afghanistan,+les+tresors+retrouves]</ref> 
Numerous interactions with the [[Mauryan Empire]], and the later expansion of the [[Indo-Greek Kingdom|Indo-Greeks]] into India suggest that transmission of Greek astronomical ideas to India occurred during this period.<ref>Pierre Cambon, Jean-François Jarrige. "Afghanistan, les trésors retrouvés: Collections du Musée national de Kaboul". Éditions de la Réunion des musées nationaux, 2006 – 297 pages. p. 269 [https://books.google.com/books?id=xJFtQgAACAAJ&q=afghanistan,+les+tresors+retrouves] "Les influences de l'astronomie grecques sur l'astronomie indienne auraient pu commencer de se manifester plus tot qu'on ne le pensait, des l'epoque Hellenistique en fait, par l'intermediaire des colonies grecques des Greco-Bactriens et Indo-Grecs" (French) Afghanistan, les trésors retrouvés", p. 269. Translation: "The influence of Greek astronomy on Indian astronomy may have taken place earlier than thought, as soon as the Hellenistic period, through the agency of the Greek colonies of the Greco-Bactrians and the Indo-Greeks.</ref> 
The Greek concept of a spherical Earth surrounded by the spheres of planets, further influenced the astronomers like [[Varahamihira]] and [[Brahmagupta]].<ref name="Pingree (1978), 533, 554f.">D. Pingree: "History of Mathematical Astronomy in India", ''Dictionary of Scientific Biography'', Vol. 15 (1978), pp. 533–633 (533, 554f.)</ref><ref name=Clemency>{{cite book |last1=Williams |first1=Clemency |last2=Knudsen |first2=Toke |editor=Glick, Tomas F. |editor-link=Thomas F. Glick |editor2=Livesey, Steven John |editor3=Wallis, Faith |title=Medieval Science, Technology, and Medicine: An Encyclopedia |chapter-url=https://books.google.com/books?id=SaJlbWK_-FcC&pg=FA463 |date=2005 |publisher=Routledge |isbn=978-0-415-96930-7 |pages=463 |chapter=South-Central Asian Science}}</ref>

Several Greco-Roman astrological treatises are also known to have been exported to India during the first few centuries of the present era. The ''[[Yavanajataka]]'' is a Sanskrit text of the 3rd century CE on Greek horoscopy and mathematical astronomy.<ref name="Andersen"/> [[Rudradaman I|Rudradaman]]'s capital at Ujjain "became the Greenwich of Indian astronomers and the Arin of the Arabic and Latin astronomical treatises; for it was he and his successors who encouraged the introduction of Greek horoscopy and astronomy into India."<ref>Pingree, David "Astronomy and Astrology in India and Iran" ''Isis'', Vol. 54, No. 2 (Jun. 1963), pp. 229–246</ref>

Later in the 6th century, the ''[[Romaka Siddhanta]]'' ("Doctrine of the Romans"), and the ''[[Paulisa Siddhanta]]'' ("Doctrine of [[Paulus Alexandrinus|Paul]]") were considered as two of the five main astrological treatises, which were compiled by [[Varāhamihira]] in his ''Pañca-siddhāntikā'' ("Five Treatises"), a compendium of Greek, Egyptian, Roman and Indian astronomy.<ref>{{cite encyclopedia |quote=Varāhamihira's knowledge of Western astronomy was thorough. In five sections, his monumental work progresses through native Indian astronomy and culminates in two treatises on Western astronomy, showing calculations based on Greek and Alexandrian reckoning and even giving complete Ptolemaic mathematical charts and tables. |encyclopedia=Encyclopædia Britannica |url=https://www.britannica.com/biography/Varahamihira |title=Varahamihira}}</ref> Varāhamihira goes on to state that "The Greeks, indeed, are foreigners, but with them this science (astronomy) is in a flourishing state."<ref name="Naskar"/> Another Indian text, the ''Gargi-Samhita'', also similarly compliments the Yavanas (Greeks) noting they, though barbarians, must be respected as seers for their introduction of astronomy in India.<ref name="Naskar"/>

===Indian and Chinese astronomy===
Indian astronomy reached China with the expansion of [[Buddhism]] during the [[Han dynasty|Later Han]] period (25–220 CE).<ref name=OhashiChina/> Further translation of Indian works on astronomy was completed in China by the [[Three Kingdoms|Three Kingdoms era]] (220–265 CE).<ref name=OhashiChina>See Ōhashi (2008) in ''Astronomy: Indian Astronomy in China''.</ref> However, the most detailed incorporation of Indian astronomy occurred only during the [[Tang dynasty]] (618–907 CE) when a number of Chinese scholars{{snd}}such as [[Yi Xing]]{{snd}}were versed both in Indian and [[Chinese astronomy]].<ref name=OhashiChina/> A system of Indian astronomy was recorded in China as ''Jiuzhi-li'' (718 CE), the author of which was an Indian by the name of [[Gautama Siddha|Qutan Xida]]{{snd}}a translation of Devanagari Gotama Siddha{{snd}}the director of the Tang dynasty's national astronomical observatory.<ref name=OhashiChina/>

Fragments of texts during this period indicate that [[Arab]]s adopted the [[Trigonometric function|sine function]] (inherited from Indian mathematics) instead of the [[chord (geometry)|chord]]s of [[Arc (geometry)|arc]] used in [[Greek mathematics|Hellenistic mathematics]].<ref name=Dallal162>Dallal, 162</ref> Another Indian influence was an approximate formula used for timekeeping by [[Astronomy in medieval Islam|Muslim astronomers]].<ref>King, 240</ref> Through Islamic astronomy, Indian astronomy had an influence on European astronomy via [[Arabic language|Arabic]] translations. During the [[Latin translations of the 12th century]], [[Muhammad al-Fazari]]'s ''Great Sindhind'' (based on the ''[[Surya Siddhanta]]'' and the works of [[Brahmagupta]]), was translated into [[Latin]] in 1126 and was influential at the time.<ref>Joseph, 306</ref>

===Indian and Islamic astronomy===
Many Indian works on astronomy and astrology were translated into [[Middle Persian]] in [[Gundeshapur]], the [[Sasanian Empire]], and later translated from Middle Persian into Arabic.{{citation needed|reason=There is reason to believe the [[House of wisdom|Bayt al-Ḥikmah]] translated many Sanskrit works into Arabic, but we need good citations to confirm that|date=December 2021}}

In the 17th century, the [[Mughal Empire]] saw a synthesis between Islamic and Hindu astronomy, where Islamic observational instruments were combined with Hindu computational techniques. While there appears to have been little concern for planetary theory, Muslim and Hindu astronomers in India continued to make advances in observational astronomy and produced nearly a hundred ''[[Zij]]'' treatises. [[Humayun]] built a personal observatory near [[Delhi]], while [[Jahangir]] and [[Shah Jahan]] were also intending to build observatories but were unable to do so. After the decline of the Mughal Empire, it was a Hindu king, [[Jai Singh II of Amber]], who attempted to revive both the Islamic and Hindu traditions of astronomy which were stagnant in his time. In the early 18th century, he built several large observatories called [[Yantra Mandir]]s, to rival [[Ulugh Beg]]'s [[Samarkand]] [[Ulugh Beg Observatory|observatory]] and to improve on the earlier Hindu computations in the ''Siddhantas'' and Islamic observations in ''[[Zij-i-Sultani]]''. The instruments he used were influenced by Islamic astronomy, while the computational techniques were derived from Hindu astronomy.<ref>Sharma (1995), 8–9</ref><ref>Baber, 82–89</ref>

===Indian astronomy and Europe===
Some scholars have suggested that knowledge of the results of the [[Kerala school of astronomy and mathematics]] may have been transmitted to Europe through the trade route from [[Kerala]] by traders and [[Jesuit]] missionaries.<ref name=almeida/> Kerala was in continuous contact with China, [[Arabia]] and Europe. The existence of circumstantial evidence<ref>Raju (2001)</ref> such as communication routes and a suitable chronology certainly make such a transmission a possibility. However, there is no direct evidence by way of relevant manuscripts that such a transmission took place.<ref name=almeida>Almeida etc. (2001)</ref>

In the early 18th century, [[Jai Singh II of Amber]] invited European [[Jesuit]] astronomers to one of his [[Yantra Mandir]] observatories, who had bought back the astronomical tables compiled by [[Philippe de La Hire]] in 1702. After examining La Hire's work, Jai Singh concluded that the observational techniques and instruments used in European astronomy were inferior to those used in India at the time – it is uncertain whether he was aware of the [[Copernican Revolution]] via the Jesuits.<ref>Baber, 89–90</ref> He did, however, employ the use of [[telescope]]s. 
In his ''Zij-i Muhammad Shahi'', he states: "telescopes were constructed in my kingdom and using them a number of observations were carried out".<ref>{{cite book |title=History of oriental astronomy: proceedings of the joint discussion-17 at the 23rd General Assembly of the International Astronomical Union, organised by the Commission 41 (History of Astronomy), held in Kyoto, August 25–26, 1997 |author=S. M. Razaullah Ansari |publisher=[[Springer Science+Business Media|Springer]] |isbn=978-1-4020-0657-9 |page=141 |year=2002}}</ref>

Following the arrival of the British [[East India Company]] in the 18th century, the Hindu and Islamic traditions were slowly displaced by European astronomy, though there were attempts at harmonising these traditions. The Indian scholar [[Mir Muhammad Hussain]] had travelled to England in 1774 to study Western science and, on his return to India in 1777, he wrote a Persian treatise on astronomy. He wrote about the heliocentric model, and argued that there exists an infinite number of [[universe]]s (''awalim''), each with their own planets and stars, and that this demonstrates the [[omnipotence]] of God, who is not confined to a single universe.<ref>{{citation |title=History of oriental astronomy: proceedings of the joint discussion-17 at the 23rd General Assembly of the International Astronomical Union, organised by the Commission 41 (History of Astronomy), held in Kyoto, August 25–26, 1997 |author=S. M. Razaullah Ansari |publisher=[[Springer Science+Business Media|Springer]] |year=2002 |isbn=978-1-4020-0657-9 |pages=133–134}}</ref> The last known ''Zij'' treatise was the ''Zij-i Bahadurkhani'', written in 1838 by the Indian astronomer [[Ghulam Hussain Jaunpuri]] (1760–1862) and printed in 1855, dedicated to [[Bahadur Khan]]. The treatise incorporated the heliocentric system into the ''Zij'' tradition.<ref>{{citation |title=History of oriental astronomy: proceedings of the joint discussion-17 at the 23rd General Assembly of the International Astronomical Union, organised by the Commission 41 (History of Astronomy), held in Kyoto, August 25–26, 1997 |author=S. M. Razaullah Ansari |publisher=[[Springer Science+Business Media|Springer]] |year=2002 |isbn=978-1-4020-0657-9 |page=138}}</ref>

==Schools and organisations of astronomy==
===Jantar Mantar===
{{Further|Jantar Mantar}}
{{See also|Jantar Mantar, Jaipur}}
Jantar (means yantra, machine); mantar (means calculate). [[Jai Singh II]] in the 18th century took great interest in science and astronomy. He made various [[Jantar Mantar]]s in [[Jaipur]], [[Jantar Mantar, New Delhi|Delhi]], [[Jantar Mantar, Ujjain|Ujjain]], [[Jantar Mantar, Varanasi|Varanasi]] and [[Mathura]]. The [[Jantar Mantar, Jaipur|Jaipur instance]] has 19 different astronomical calculators. These comprise live and forward-calculating astronomical clocks (calculators) for days, eclipses, visibility of key constellations which are not year-round northern polar ones thus principally but not exclusively those of the zodiac. [[Astronomer]]s abroad were invited and admired complexity of certain devices.
[[File:Jantar Delhi.jpg|thumb|right|[[Yantra Mandir]] (completed by 1743 CE), [[Delhi]].]]
[[File:Grad-Scale-Hindu-Arabic-numerals.jpg|thumb|Samrat yantra with divisions of hours, minutes and seconds]]
As brass time-calculators are imperfect, and to help in their precise re-setting so as to match true locally experienced time, there remains equally his Samrat Yantra, the largest sundial in the world. It divides each daylit hour as to solar 15-minute, 1-minute and 6-second subunits.<ref>{{Cite web |title=Samrat Yantra |url=http://www.jantarmantar.org/learn/observatories/instruments/samrat/index.html |website=Jantar Mantar |language=en}}</ref> Other notable include:
*Nadivalaya yantra<ref>{{Cite web |title=Nadivalaya Yantra |url=http://www.jantarmantar.org/learn/observatories/instruments/nadivalaya/index.html |website=Jantar Mantar |language=en}}</ref>
*Rama Yantra<ref>{{Cite web |title=Rama Yantra |url=http://www.jantarmantar.org/learn/observatories/instruments/rama/index.html |website=Jantar Mantar |language=en}}</ref>
*Daksinottara Bhitti<ref>[https://www.jantarmantar.org/learn/observatories/instruments/daksinottara%20Bhitti/index.html Daksinottara Bhitti at jantarmantar.org]{{Dead link|date=July 2023 |bot=InternetArchiveBot |fix-attempted=yes }}</ref>
*Unnatamsha Yantra<ref>{{Cite web |title=Unnatamsha Yantra |url=http://www.jantarmantar.org/learn/observatories/instruments/unnatamsha/index.html |website=Jantar Mantar |language=en}}</ref>
*Jai Prakash yantra<ref>{{Cite web |title=Jai Prakash |url=http://www.jantarmantar.org/learn/observatories/instruments/jaiPrakash/index.html |website=Jantar Mantar |language=en}}</ref>
[[File:Kapali Yantra.jpg|thumb|Kapali Yantra at Jantar Mantar, Jaipur]]
[[File:Laghu samrat yantra.JPG|thumb|Laghu samrat yantra]]

===Kerala school of astronomy and mathematics===
{{Further|Kerala school of astronomy and mathematics}}
Models of the Kerala school (active 1380 to 1632) involved higher order [[polynomial]]s and other cutting-edge algebra; many neatly were put to use, principally for predicting motions and alignments within the Solar System.<ref>[[Otto Neugebauer]] (1952) "Tamil Astronomy", [[Osiris (journal)|Osiris]] 10: 252–276</ref><ref>{{Cite journal |last1=Ramasubramanian |first1=K. |last2=Srinivas |first2=M. D. |last3=Sriram |first3=M. S. |date=25 May 1994 |title=Modification of the earlier Indian planetary theory by the Kerala astronomers (c. 1500 AD) and the implied heliocentric picture of planetary motion |url=https://www.jstor.org/stable/24098820 |journal=[[Current Science]] |volume=66 |issue=10 |pages=784–790 |jstor=24098820 |issn=0011-3891}}</ref><ref>{{Cite book |last=Warren |first=John |url=https://books.google.com/books?id=nttCAAAAcAAJ |title=A Collection of Memoirs on the Various Modes According to which the Nations of the Southern Parts of India Divide Time |publisher= |year=1825 |language=en}}</ref>

==20th and 21st Century==
===Astronomers===
During 1920, astronomers like [[Sisir Kumar Mitra]], [[C.V. Raman]] and [[Meghnad Saha]] worked on various projects such as sounding of the [[ionosphere]] through ground-based radio and the [[Saha ionisation equation]]. [[Homi J. Bhabha|Homi J. Bhaba]] and [[Vikram Sarabhai]] made significant contributions.{{sfn|Daniel|1992}} [[A. P. J. Abdul Kalam]] also known as ''Missile Man of India'' assisted in development and research for the [[Defence Research and Development Organisation]] and the Indian Space Research Organisation's (ISRO) civilian space programme and [[launch vehicle]] technology.<ref>{{cite book |title=A to C (Abd Allah ibn al-Abbas to Cypress). |date=2000 |publisher=Encyclopædia Britannica (India) |location=New Delhi |isbn=978-0-85229-760-5 |page=2 |url=https://books.google.com/books?id=Kpd9lLY_0-IC |author=Ramchandani |editor=Dale Hoiberg |access-date=10 August 2019 |archive-url=https://web.archive.org/web/20160829192223/https://books.google.com/books?id=Kpd9lLY_0-IC |archive-date=29 August 2016 |url-status=live}}</ref><ref>{{cite book |first=R. K. |last=Pruthi |url=https://books.google.com/books?id=Ee3PR5HFBCAC |title=President A.P.J. Abdul Kalam |publisher=Anmol Publications |date=2005 |isbn=978-81-261-1344-6 |chapter=4. Missile Man of India |pages=61–76}}</ref><ref>{{cite web |url=http://www.torontosun.com/2015/07/29/indias-mr-missile-a-man-of-the-people?token=8bebcb17cfd851eb0bc06642519e8767 |title=India's 'Mr. Missile': A man of the people |access-date=30 July 2015 |date=30 July 2015 |url-status=live |archive-url=https://web.archive.org/web/20150925135024/http://www.torontosun.com/2015/07/29/indias-mr-missile-a-man-of-the-people?token=8bebcb17cfd851eb0bc06642519e8767 |archive-date=25 September 2015}}</ref>

===Organizations===
Bhaba established the [[Tata Institute of Fundamental Research]] and Vikram Sarabhai established the [[Physical Research Laboratory]]. These organisations researched [[cosmic radiation]] and conducted studies of the [[upper atmosphere]].{{sfn|Daniel|1992}} In 1950, the [[Department of Atomic Energy]] was founded with Bhaba as secretary and provided funding to space researches in the country.{{sfn|Daniel|1992}} The [[Indian National Committee for Space Research]] (INCOSPAR) was founded in 1962 on the urging of Sarabhai.{{sfn|Sadeh|2013}}{{sfn|Bhargava|Chakrabarti|2003}} ISRO succeeded INCOSPAR and the [[Department of Space]] (under [[Indira Gandhi]]) was established, thereby institutionalising astronomical research in India.{{sfn|Bhargava|Chakrabarti|2003}}<ref>{{Cite web |url=https://www.isro.gov.in/about-isro/department-of-space-and-isro-hq |title=Department of Space and ISRO HQ – ISRO |access-date=28 March 2019 |archive-url=https://web.archive.org/web/20190328053630/https://www.isro.gov.in/about-isro/department-of-space-and-isro-hq |archive-date=28 March 2019 |url-status=live}}</ref> Organisations like [[SPARRSO]] in Bangladesh,<ref>{{cite web |url=http://www.sparrso.gov.bd/ |title=বাংলাদেশ মহাকাশ গবেষণা ও দূর অনুধাবন}}</ref> [[SUPARCO]] in Pakistan<ref>{{cite web |url=http://www.suparco.gov.pk/ |title=SUPARCO |access-date=22 July 2023 |archive-date=2 April 2015 |archive-url=https://web.archive.org/web/20150402152438/http://suparco.gov.pk/ |url-status=dead}}</ref> and others were founded shortly after.

===Space programmes and research===
* ISRO played a role in the discovery of three species of extremophile bacteria in the upper stratosphere at an altitude between 20–40 km which are highly resistant to ultra-violet radiation, which are named as ''[[Bacillus isronensis]]'', ''Bacillus aryabhattai'' (in recognition of ISRO's contribution) and [[Janibacter hoylei]].<ref>{{cite journal |last1=Harris |first1=Melanie J. |last2=Wickramasinghe |first2=N. C. |last3=Lloyd |first3=David |display-authors=etal |year=2002 |issue=Instruments, Methods, and Missions for Astrobiology IV |doi=10.1117/12.454758 |journal=Proc. SPIE |volume=4495 |title=Detection of living cells in stratospheric samples |page=192 |series=Instruments, Methods, and Missions for Astrobiology IV |url=http://repository.iucaa.in:8080/jspui/bitstream/11007/1631/1/295aB_2002.pdf |access-date=21 September 2019 |archive-url=https://web.archive.org/web/20170922023031/http://repository.iucaa.in:8080/jspui/bitstream/11007/1631/1/295aB_2002.pdf |archive-date=22 September 2017 |url-status=live |bibcode=2002SPIE.4495..192H |s2cid=129736236}}</ref><ref>{{cite journal |last1=Shivaji |first1=S. |last2=Chaturvedi |first2=P. |last3=Begum |first3=Z. |display-authors=etal |year=2009 |title=''Janibacter hoylei'' sp.nov., ''Bacillus isronensis'' sp.nov. and ''Bacillus aryabhatta'' sp.nov. isolated from cryotubes used for collecting air from the upper atmosphere |journal=International Journal of Systematic and Evolutionary Microbiology |volume=59 |issue=12 |pages=2977–2986 |doi=10.1099/ijs.0.002527-0 |pmid=19643890 |doi-access=free}}</ref>
* [[Astrosat]], a [[space observatory]] launched in 2015 by ISRO, detected a [[gamma-ray burst]] in January 2017, captured a rare phenomenon of a 6-billion-year-old [[blue straggler]] feeding off and sucking out mass and energy out of a bigger star and detected a rare [[X-ray burster|X-ray outburst]] in a [[Be/X-ray binary]] system RX J0209.6-7427.<ref>{{Cite web |url=https://www.isro.gov.in/update/28-sep-2018/three-years-of-astrosat |title=Three years of AstroSat – ISRO |website=www.isro.gov.in |language=en |access-date=28 September 2018 |archive-url=https://web.archive.org/web/20190830213436/http://isro.gov.in/update/28-sep-2018/three-years-of-astrosat |archive-date=30 August 2019 |url-status=live}}</ref><ref>{{Cite news |url=http://www.thehindu.com/sci-tech/science/astrosat-rules-out-afterglow-in-black-hole-merger/article19094393.ece |title=AstroSat rules out afterglow in black hole merger |newspaper=The Hindu |date=2017-06-17 |last1=Desikan |first1=Shubashree}}</ref><ref>{{Cite web |url=http://indianexpress.com/article/technology/tech-news-technology/vampire-star-caught-in-the-act-by-indian-space-observatory-4498660/ |title='Vampire' star caught in the act by Indian space observatory ASTROSAT |date=2017-01-30}}</ref><ref>
{{cite journal |author1=Chandra, A. D. |author2=Roy, J. |author3=Agrawal, P. C. |author4=Choudhury, M. |title=Study of recent outburst in the Be/X-ray binary RX J0209.6−7427 with AstroSat: a new ultraluminous X-ray pulsar in the Magellanic Bridge? |journal=Monthly Notices of the Royal Astronomical Society |date=2020 |volume=495 |issue=3 |pages=2664–2672 |doi=10.1093/mnras/staa1041 |doi-access=free |bibcode=2020MNRAS.495.2664C |arxiv=2004.04930 |s2cid=215737137}}</ref>
* <!-- to be shortened later-->[[Chandrayaan-3]] is the third mission in the [[Chandrayaan programme]], a series of [[Exploration of the Moon|lunar-exploration]] missions developed by the ISRO.<ref>{{Cite news |last1=Kumar |first1=Hari |last2=Travelli |first2=Alex |last3=Mashal |first3=Mujib |last4=Chang |first4=Kenneth |date=23 August 2023 |title=India Moon Landing: In Latest Moon Race, India Lands First in Southern Polar Region |work=The New York Times |url=https://www.nytimes.com/live/2023/08/23/science/india-moon-landing-chandrayaan-3 |url-status=live |access-date=26 August 2023 |archive-url=https://web.archive.org/web/20230826034411/https://www.nytimes.com/live/2023/08/23/science/india-moon-landing-chandrayaan-3 |archive-date=26 August 2023 |issn=0362-4331}}</ref> It objectivized to conduct soft landing on [[Lunar south pole]], observing & demonstrating the rover's driving capabilities on the Moon and conducting experiments on the materials available on the lunar surface to better understand the composition of the Moon.<ref>{{Cite web |title=Chandrayaan-3 Details |url=https://www.isro.gov.in/Chandrayaan3_Details.html |url-status=live |archive-url=https://web.archive.org/web/20230823165138/https://www.isro.gov.in/Chandrayaan3_Details.html |archive-date=23 August 2023 |access-date=24 August 2023 |website=Indian Space Research Organisation}}</ref> The launch was done on 14 July 2023 at the [[Satish Dhawan Space Centre]]. The lander and rover successfully landed at the [[Lunar south pole|south pole of moon]] on 23 August 2023.<ref>{{Cite news |date=23 August 2023 |title=India Is on the Moon: Lander's Success Moves Nation to Next Space Chapter |language=en |work=The New York Times |url=https://www.nytimes.com/2023/08/23/science/chandrayaan-3-india-moon-landing.html |url-status=live |access-date=23 August 2023 |archive-url=https://web.archive.org/web/20230823172509/https://www.nytimes.com/2023/08/23/science/chandrayaan-3-india-moon-landing.html |archive-date=23 August 2023}}</ref>

==See also==

{{Portal|India|Astronomy}}
{{col div|colwidth=25em}}
*[[Astronomical basis of the Hindu calendar]]
*[[Astronomy in the medieval Islamic world]]
*[[Buddhist cosmology]]
*[[Chinese astronomy]]
*[[Hindu calendar]]
*[[Hindu astrology]]
*[[Hindu units of time|Hindu chronology]]
*[[Hindu cosmology]]
*[[History of astronomy]]
*[[Jain cosmology]]
*[[List of numbers in Hindu scriptures]]
*[[Nirayana system]]

{{colend}}{{Clear}}

==References==
{{Reflist}}

==Bibliography==

{{Refbegin|30em}}
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{{Refend}}

==Further reading==
*[[Project of History of Indian Science, Philosophy and Culture|Project of History of Indian Science, Philosophy and culture]], Monograph series, Volume 3. ''Mathematics, Astronomy and Biology in Indian Tradition'' edited by D. P. Chattopadhyaya and Ravinder Kumar
*{{Citation |last=Brennand |first=William |title=Hindu Astronomy |url=https://archive.org/stream/hinduastronomy00brenuoft#page/n7/mode/2up |year=1896 |publisher=Chas.Straker & Sons, London}}
* {{Citation |last=Maunder |first=E. Walter |title=The Indian Eclipse 1898 |url=https://archive.org/stream/indianeclipserep00britrich#page/n7/mode/2up |year=1899 |publisher=Hazell Watson and Viney Ltd., London}}
* [[Subhash Kak|Kak, Subhash]]. ''Birth and early development of Indian astronomy''. Kluwer, 2000.
* Kak, S. (2000). ''The astronomical code of the R̥gveda''. New Delhi: [[Munshiram Manoharlal]] Publishers.
* Kak, Subhash C. "The astronomy of the age of geometric altars." ''[[Quarterly Journal of the Royal Astronomical Society]]'' 36 (1995): 385.
* Kak, Subhash C. "Knowledge of planets in the third millennium BC." ''[[Quarterly Journal of the Royal Astronomical Society]]'' 37 (1996): 709.
* Kak, S. C. (1 January 1993). Astronomy of the vedic altars. ''Vistas in Astronomy: Part 1'', 36, 117–140.
* Kak, Subhash C. "Archaeoastronomy and literature." ''Current Science'' 73.7 (1997): 624–627.

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