{{Short description|Muslim astronomer and mathematician (died 929)}}
{{Redirect|Albategnius|the lunar crater|Albategnius (crater)}}
{{good article}}
{{Lowercase title}}
{{Use British English|date=January 2023}}
{{Infobox academic
| image = Latin 7266; folio 78r (BnF).jpg
| image_size = 180
| caption = A [[folio]] from a [[Latin]] translation of {{transliteration|ar|Kitāb az-Zīj aṣ-Ṣābi’}} ({{circa|900}}), Latin 7266, {{lang|fr|[[Bibliothèque nationale de France]]}}
| name = al-Battānī
| native_name = محمد بن جابر بن سنان البتاني
| native_name_lang = ar
| birth_date = Before 858
| birth_place = [[Harran]], [[Bilad al-Sham|Islamic Syria]] (modern-day Turkey)
| death_date = 929
| death_place = Qasr al-Jiss, near [[Samarra]]
| era = [[Islamic Golden Age]]
| school_tradition = 
| main_interests = [[Islamic mathematics|Mathematics]], [[Islamic astronomy|astronomy]], [[astrology]]
| notable_ideas = {{Unbulleted list|[[Trigonometry|Trigonometrical relationships]]}}
| major_works = {{transliteration|ar|Kitāb az-Zīj}}
| influences = 
| influenced = 
}}
'''Al-Battani{{efn|{{langx|ar|{{larger|البتاني}}}}; [[Arabic name|full name]] in {{Langx|ar|أبو عبد الله محمد بن جابر بن سنان الرقي الحراني السابع البتاني|translit=Abū ʿAbd Allāh Muḥammad ibn Jābir ibn Sinān al-Raqqī al-Ḥarrānī aṣ-Ṣābiʾ al-Battānī|links=no}}}}''' (before 858{{snd}}929), archaically [[Latinization (literature)|Latinized]] as '''Albategnius''',{{Efn|He was also known in the West as Albategni or Albatenius.{{sfn|Zamani|2014}}}} was an [[Arab]]<ref>{{cite encyclopedia |title=al-Battani |encyclopedia=Encyclopædia Britannica |url=https://www.britannica.com/biography/al-Battani |access-date=11 December 2025 |quote=al-Battani ... was an Arab astronomer and mathematician who developed improved methods for calculating the positions of celestial bodies.}}</ref><ref>{{cite web |title=Al-Battani |url=https://www.oxfordreference.com/view/10.1093/oi/authority.20110803095359912 |access-date=11 December 2025 |work=Oxford Reference |quote=(c. 858–929) Arab astronomer. Al-Battani was the son of a maker of astronomical instruments in Harran.}}</ref><ref>{{cite encyclopedia |year=1911 |title=Albategnius |encyclopedia=Encyclopædia Britannica |publisher=Cambridge University Press |edition=11th |page=498 |quote=Al-Batani (Albategnius) was an Arab prince and astronomer of Harran.}}</ref> [[Muslim]] [[Islamic astronomy|astronomer]], [[astrologer]], [[geographer]] and [[Islamic mathematics|mathematician]], who lived and worked for most of his life at [[Raqqa]], now in Syria. He is considered to be one of the greatest and most famous of the [[Astronomy in the medieval Islamic world|astronomers of the medieval Islamic world]].

Al-Battānī's writings became instrumental in the development of science and astronomy in the west. His {{transliteration|ar|Kitāb az-Zīj aṣ-Ṣābi’}} ({{circa|900}}), is the earliest extant {{transliteration|ar|zīj}} (astronomical table) made in the [[Geocentrism|Ptolemaic tradition]] that is hardly influenced by Hindu or Sasanian astronomy. Al-Battānī refined and corrected [[Ptolemy]]'s ''[[Almagest]]'', but also included new ideas and astronomical tables of his own. A handwritten [[Latin]] version by the Italian astronomer [[Plato Tiburtinus]] was produced between 1134 and 1138, through which medieval astronomers became familiar with al-Battānī. In 1537, a Latin translation of the {{transliteration|ar|zīj}} was printed in [[Nuremberg]]. An annotated version, also in Latin, published in three separate volumes between 1899 and 1907 by the Italian Orientalist [[Carlo Alfonso Nallino]], provided the foundation of the modern study of medieval Islamic astronomy.

Al-Battānī's observations of the Sun led him to understand the nature of [[annular solar eclipse]]s. He accurately calculated the Earth's [[Axial tilt|obliquity]] (the angle between the planes of the [[equator]] and the [[ecliptic]]), the solar year, and the [[equinox]]es (obtaining a value for the [[precession of the equinoxes]] of one degree in 66 years). The accuracy of his data encouraged [[Nicolaus Copernicus]] to pursue ideas about the [[heliocentric]] nature of the cosmos. Al-Battānī's tables were used by the German mathematician [[Christopher Clavius]] in reforming the [[Julian calendar]], and the astronomers [[Tycho Brahe]], [[Johannes Kepler]], [[Galileo Galilei]] and [[Edmund Halley]] all used Al-Battānī's observations.

Al-Battānī introduced the use of [[sine]]s and [[tangent (trigonometric function)|tangent]]s in [[geometrical]] calculations, replacing the geometrical methods of the Greeks. Using [[trigonometry]], he created an equation for finding the {{transliteration|ar|[[qibla]]}} (the direction which Muslims need to face during their [[Salah|prayers]]). His equation was widely used until superseded by more accurate methods, introduced a century later by the [[polymath]] [[al-Biruni]].

==Life==
Al-Battānī, whose full name was {{transliteration|ar|Abū ʿAbd Allāh Muḥammad ibn Jābir ibn Sinān al-Raqqī al-Ḥarrānī al-Ṣābiʾ al-Battānī|italics=no}}, and whose Latinized name was {{transliteration|la|Albategnius|italic=no}}, was born before 858 in [[Harran]] in [[Bilad al-Sham|Bilād ash-Shām]] (Islamic Syria), {{convert|44|km}} southeast of the modern Turkish city of [[Urfa]]. He was the son of Jabir ibn Sinan al-Harrani, a maker of astronomical instruments.{{sfn|Angelo|2014|p=78}} The [[epithet]] {{transliteration|ar|al-Ṣabi’}} suggests that his family belonged to the [[Harranians|pagan Sabian sect of Harran]],{{sfn|de Blois|2012}}<ref name="OCoRob" /> whose religion featured [[star worship]], and who had inherited the [[Mesopotamia]]n legacy of an interest in mathematics and astronomy.{{sfn|Zamani|2014}}{{Efn|According to the ''History of Learned Men'' by [[Ibn al-Qifti]], writing in the 13th century, al-Battānī's recorded astronomical observations date from 877, and it has been suggested that he was born before 858. Al-Qifti wrote that al-Battani's {{transliteration|ar|zīj}} included observations of the Sun and the Moon that corrected Ptolemy's ''[[Almagest]]'', and that al-Battani ceased observing in 918, and died in 929.{{sfn|Freely|2010|p=61}}}} His contemporary, the polymath [[Thābit ibn Qurra]], was also an adherent of Sabianism, which died out during the 11th century.{{sfn|Ronan|1983|p=208}}
 
Although his ancestors were likely Sabians, al-Battānī was a Muslim, as shown by his first name.<ref name="OCoRob" /> Between 877 and 918/19 he lived in [[Raqqa]], now in north central Syria, which was an ancient Roman settlement beside the [[Euphrates]], near Harran. During this period he also lived in [[Antioch]],{{sfn|Angelo|2014|p=78}} where he observed a [[Solar eclipse|solar]] and a [[lunar eclipse]] in 901. According to the Arab biographer [[Ibn al-Nadīm]], the financial problems encountered by al-Battānī in old age forced him to move from Raqqa to [[Baghdad]].{{sfn|Van Dalen|2007}}

Al-Battānī died in 929 at Qasr al-Jiss,{{sfn|Zamani|2014}} near [[Samarra]], after returning from Baghdad where he had resolved an unfair taxation grievance on behalf of a clan from Raqqa.{{sfn|Angelo|2014|p=79}}

==Astronomy==
Al-Battānī is considered to be the greatest{{sfn|Schlager|Lauer|2001|p=291}}{{sfn|Griffin|2006|p=31}}<ref name=Ben-Menaḥem>{{cite encyclopedia |last1=Ben-Menaḥem |first1=Ari |author-link=Ari Ben-Menahem |entry = 877–910 CE Muhammad al-Battani; Albategnius | title=Historical Encyclopedia of Natural and Mathematical Sciences |date=2009 |publisher=Springer |location=Berlin |isbn=978-3-540-68831-0 |page=541 |volume=1: Prescience-1583 CE |doi=10.1007/978-3-540-68832-7_5}}</ref> and most famous of the known [[Astronomy in the medieval Islamic world|astronomers of the medieval Islamic world]]. He made more accurate observations of the night sky than any of his contemporaries,{{sfn|Angelo|2014|p=78}} and was the first of a generation of new Islamic astronomers that followed the founding of the [[House of Wisdom]] in the 8th century.{{sfn|Freely|2010|p=60}} His meticulously described methods allowed others to assess his results, but some of his explanations about the movements of the planets were poorly written, and have mistakes.{{sfn|North|1994|p=187}}

Sometimes referred to as the "Ptolemy of the Arabs",{{sfn|Wurm|2020|p=17}} al-Battānī's works reveal him to have been a devout believer in [[Ptolemy]]'s [[geocentric model]] of the cosmos. He refined the observations found in Ptolemy's {{lang|el|Almagest}},{{sfn|Angelo|2014|p=78}} and compiled new tables of the Sun and the Moon, previously long accepted as authoritative.<ref name="OCoRob" /> Al-Battānī established his own observatory at Raqqa. He recommended that the astronomical instruments there were greater than {{convert|1|m|spell=in}} in size.{{sfn|Van Dalen|2007}} Such instruments, being larger—and so having scales capable of measuring smaller values—were capable of greater [[Accuracy and precision|precision]] than had previously been achieved.{{sfn|McLeod|2016|p=160}} Some of his measurements were more accurate than those taken by the Polish astronomer and mathematician [[Nicolaus Copernicus]] during the [[Renaissance]]. One reason for this is thought to be that al-Battānī's location for his observations at Raqqa was closer to the Earth's [[equator]], so that the [[ecliptic]] and the Sun, being higher in the sky, were less susceptible to [[atmospheric refraction]].<ref name="OCoRob" /> The careful construction and alignment of his astronomical instruments enabled him to achieve an accuracy of observations of [[equinox]]es and [[solstice]]s that had previously been unknown.{{sfn|Van Dalen|2007}}

{{multiple image | direction = horizontal | total_width= 350 | header = | footer = | image1 = May 20, 2012 Eclipse, seen from Wolfforth, Texas, USA.JPG | alt1 = | caption1 =An [[annular solar eclipse]]. Al-Battānī was one of the first astronomers to understand why such phenomena can occur.| image2 = The Earth's ecliptic and celestial equator.svg | alt2 =| caption2 = A representation of the [[celestial equator]] and Earth's [[ecliptic]]}}
Al-Battānī was one of the first astronomers to observe that the distance between the Earth and the Sun varies during the year, which led him to understand the reason why [[annular solar eclipse]]s occur.{{sfn|Angelo|2014|p=78}}<ref name="Gal">{{cite journal |title=Al-Battānī, Abū 'Abd Allāh Muḥammad Ibn Jābir Ibn Sinān Al-Raqqī Al-Ḥarrānī Al-Ṣābi' |journal=Dictionary of Scientific Biography |date=2008 |volume=1 |pages=507{{ndash}}516 |url=https://link.gale.com/apps/doc/CX2830900300/GVRL?u=norm94900&sid=GVRL&xid=c346bbce |access-date=21 January 2023 |publisher=Charles Scribner's Sons |issn=0036-8075}}</ref>{{sfn|Kennedy|2010|pp=13{{ndash}}14}} He saw that the position in the sky at which the [[angular diameter]] of the Sun appeared smallest was no longer located where Ptolemy had stated it should be,{{sfn|Angelo|2014|p=78}} and that since Ptolemy's time, the [[Longitude|longitudinal position]] of the apogee had increased by 16°47'.{{r|Ben-Menaḥem}}

Al-Battānī was an excellent observer.{{sfn|Kennedy|1956|pp=10{{ndash}}11}} He improved Ptolemy's measurement of the [[Axial tilt|obliquity of the ecliptic]] (the angle between the planes of the equator and the ecliptic),{{sfn|Angelo|2014|p=79}} producing a value of 23° 35';<ref name="OCoRob" />{{Efn|A century earlier, other Islamic astronomers had previously found values for the obliquity that came close to the value obtained by al-Battānī, changes in the solar apogee had earlier been detected by Thabit ibn Qurra (or perhaps the [[Banū Mūsā brothers]]).{{sfn|North|1994|p=187}}}} the accepted value is around 23°.44.<ref name="Inf">{{cite web |title=Glossary ("Obliquity") |url=https://aa.usno.navy.mil/faq/asa_glossary#obliquity |website=Information Center |publisher=Astronomical Applications Department [[U.S. Naval Observatory]] |access-date=23 February 2023 |archive-date=8 September 2023 |archive-url=https://web.archive.org/web/20230908233641/https://aa.usno.navy.mil/faq/asa_glossary#obliquity |url-status=live }}</ref> Al-Battānī obtained the criterion for observation of the lunar crescent—i.e., if the longitude difference between the Moon and the Sun is greater than 13° 66˝ and the Moon's delay after sunset is more than 43.2 minutes, the crescent will be visible.{{sfn|Zamani|2014}} His value for the [[Tropical year|solar year]] of 365 days, 5 hours, 46 minutes and 24 seconds, is 2 minutes and 22 seconds from the accepted value.<ref name="OCoRob">{{cite web |last1=O'Connor |first1=John J. |last2=Robertson |first2=Edmund F. |title=Abu Abdallah Mohammad ibn Jabir Al-Battānī |url=https://mathshistory.st-andrews.ac.uk/Biographies/Al-Battani/ |website=[[MacTutor History of Mathematics archive|MacTutor]] |publisher=[[University of St Andrews]] |access-date=21 January 2023 |ref=OCoRob |archive-date=17 July 2017 |archive-url=https://web.archive.org/web/20170717012428/http://www-history.mcs.st-andrews.ac.uk/Biographies/Al-Battani.html |url-status=live }}</ref>

Al-Battānī observed changes in the direction of the Sun's [[apogee]], as recorded by Ptolemy,{{sfn|Singer|1997|p=135}} and that as a result, the [[equation of time]] was subject to a slow cyclical variation.{{sfn|Nallino|1987|pp=680{{ndash}}681}} His careful measurements of when the [[March equinox|March]] and [[September equinox]]es took place allowed him to obtain a value for the [[Axial precession|precession of the equinoxes]] of 54.5" per year, or 1 [[Degree (angle)|degree]] in 66 years,<ref name="OCoRob" />{{sfn|Angelo|2014|p=79}} a phenomenon that he realised was altering the Sun's annual apparent motion through the zodiac [[constellation]]s.{{sfn|Angelo |2014|pp=78{{ndash}}79}}
 
It was impossible for al-Battānī, who adhered to the ideas of a stationary Earth and geocentricism, to understand the underlying scientific reasons for his observations or the importance of his discoveries.{{sfn|Angelo |2014|pp=78{{ndash}}79}}

==Mathematics==
{{multiple image
| direction         = horizontal
| total_width       = 300
| header            = 
| footer            = 
| image1            = Trigonometry triangle (2).svg
| alt1              = 
| caption1          = The fundamental [[trigonometric function]]s defined from a [[Right triangle|right-angled triangle]]: sine, cosine, and tangent
| image2            = Diagram for (cos A) cosine rule.svg
| alt2              = 
| caption2          = A [[Spherical trigonometry|spherical triangle]] with sides ''a'', ''b'', and ''c''
}}

One of al-Battani's greatest contributions was his introduction of the use of [[sine]]s and [[tangent (trigonometric function)|tangent]]s in [[geometrical]] calculations, especially [[Spherical trigonometry|spherical trigonometric functions]], to replace Ptolemy's geometrical methods. Al-Battānī's methods involved some of the most complex mathematics developed up to that time.{{sfn|Angelo |2014|pp=78{{ndash}}79}} He was aware of the superiority of trigonometry over [[Chord (geometry)|geometrical chords]], and demonstrated awareness of a relation between the sides and angles of a spherical triangle, now given by the expression:{{r|Ben-Menaḥem}}

::<math>\cos a = \cos b\cos c + \sin b\sin c\cos A</math>

Al-Battānī produced a number of [[Trigonometry|trigonometrical]] relationships:<ref name="Mao" />

::<math>\tan \alpha = \frac{\sin \alpha}{\cos \alpha}</math>

::<math>\sec \alpha = \sqrt{1 + \tan^2 \alpha }</math>, where <math>\sec \alpha = \frac{1}{\cos \alpha}</math>.

He also solved the equation 
::<math>\sin x = y\cos x</math>,

discovering the formula 
::<math>\sin x = \frac{y}{\sqrt{1 + y^2}}</math>

Al-Battānī used the Iranian astronomer [[Habash al-Hasib al-Marwazi]]'s idea of [[Trigonometric function|tangents]] to develop equations for calculating and compiling tables of both tangents and cotangents. He discovered their [[Multiplicative inverse|reciprocal functions]], the secant and cosecant, and produced the first table of cosecants for each degree from 1° to 90°, which he referred to as a "table of shadows", in reference to the shadow produced on a [[sundial]].<ref name=Mao>{{cite book |last=Maor |first=Eli |date=1998 |title=Trigonometric Delights |location=Princeton |publisher=Princeton University Press |page=38 |isbn=978-0-691-15820-4}}</ref>

[[File:Qibla diagram 2.svg|thumb|A geometrical representation of the method used by al-Battānī to determine the {{transliteration|ar|[[qibla]]}}, shown as ''q'' from ''O'' (the observer) to ''M'' (Mecca){{sfn|Van Brummelen|2013|pp=15{{ndash}}16}}{{Efn|From the diagram, it can be shown that:{{sfn|Van Brummelen|2013|pp=15{{ndash}}16}}
::<math>\tan q =\frac{OA}{OD} = \frac{\sin \lambda}{\sin \phi} = \frac{OA/r}{OD/r}</math>}}]]
Using these trigonometrical relationships, al-Battānī created an equation for finding the {{lang|ar|[[qibla]]}}, which Muslims face in each of the five [[Salah|prayers they practice every day]].{{sfn|Van Brummelen|2013|p=15}} The equation he created did not give accurate directions, as it did not take into account the fact that Earth is a sphere. The relationship he used was precise enough only for a person located in (or close to) [[Mecca]], but was still a widely used method at the time. Al-Battānī's equation for <math>q</math>, the angle of the direction of a place towards Mecca is given by:{{sfn|Van Brummelen|2013|pp=15{{ndash}}16}}

<math>\tan q=\frac{\sin\Delta\lambda}{\sin\Delta\phi}</math>

where <math>\Delta\lambda</math> is the difference between the longitude of the place and Mecca, and <math>\Delta\phi</math> is the difference between the latitude of the place and Mecca.

Al-Battānī's equation was superseded a century after it was first used, when the [[polymath]] [[al-Biruni]] summarized several other methods to produce results that were more accurate than those that could be obtained using al-Battānī's equation.{{sfn|Van Brummelen|2013|p=17}}

A small work on trigonometry, {{transliteration|ar|Tajrīd uṣūl tarkīb al-juyūb}} ("Summary of the principles for establishing sines") is known. Once attributed to the Iranian astronomer [[Kushyar Gilani]] by the German orientalist [[Carl Brockelmann]], it is a fragment of al-Battānī's {{transliteration|ar|zīj}}. The manuscript is extant in [[Istanbul]] as MS Carullah 1499/3.{{sfn|Zamani|2014}} The authenticity of this work has been questioned, as scholars believe al-Battānī would have not have included {{transliteration|ar|al-juyūb}} for "sines" in the title.{{sfn|Van Dalen|2007}}

== Works ==
==={{transliteration|ar|Kitāb az-Zīj aṣ-Ṣābi’}}===
Al-Battānī's {{transliteration|ar|Kitāb az-Zīj}} ({{lang|ar| كتاب الضد}} or {{lang|ar|الضد البتاني}}, "Book of Astronomical Tables"), written in around 900, and also known as the {{transliteration|ar|al-Zīj al-Ṣābī}} ({{lang|ar|كتاب الزيج الصابئ}}),{{sfn|Zamani|2014}} is the earliest extant {{transliteration|ar|zīj}} made in the Ptolemaic tradition that is hardly influenced by Hindu or Sasanian–Iranian astronomy.{{sfn|Van Dalen|2007}} It corrected mistakes made by Ptolemy and described instruments such as horizontal and vertical sundials, the [[Triquetrum (astronomy)|triquetrum]], the [[mural instrument]],{{sfn|Zamani|2014}} and a [[Quadrant (instrument)|quadrant]] instrument.{{sfn|Moussa|2011}} Ibn al-Nadim wrote that al-Battānī's {{transliteration|ar|zīj}} existed in two different editions, "the second being better than the first".{{sfn|Van Dalen|2007}} In the west, the work was sometimes called the ''Sabean Tables''.{{sfn|Freely|2010|p=61}}

The work, consisting of 57 chapters and additional tables, is extant (in the manuscript árabe 908, held in [[El Escorial]]), copied in [[Al-Andalus]] during the 12th or 13th century. Incomplete copies exist in other western European libraries.{{sfn|Van Dalen|2007}} Much of the book consists of instructions for using the attached tables. Al-Battānī used an Arabic translation of the ''Almagest'' made from [[Syriac language|Syriac]], and used few foreign terms. He copied some data directly from Ptolemy's [[Handy Tables]], but also produced his own. His star table of 880 used around half the stars found in the then 743-year-old ''Almagest''. It was made by increasing Ptolemy's stellar longitudes, to allow for the different positions of the stars, now known to be caused by precession.{{sfn|Van Dalen|2007}}

Other {{transliteration|ar|[[zīj]]es}} based on {{transliteration|ar|Kitāb az-Zīj aṣ-Ṣābi’}} include those written by Kushyar Gilani, [[Alī ibn Ahmad al-Nasawī]], Abū Rashīd Dāneshī, and [[Ibn al-Kammad]].{{sfn|Zamani|2014}}

The first version in Latin from the Arabic was made by the English astronomer [[Robert of Ketton]]; this version is now lost.{{sfn|Zamani|2014}}{{sfn|Nallino|1987|pp=680{{ndash}}681}} A Latin edition was also produced by the Italian astronomer [[Plato Tiburtinus]] between 1134 and 1138.{{sfn|Kunitzsch|1974|p=115}} Medieval astronomers became quite familiar with al-Battānī through this translation, renamed {{lang|la|De motu stellarum}} ("On stellar motion").{{sfn|Angelo|2014|p=79}} It was also translated from Arabic into Spanish during the 13th century, under the orders of [[Alphonso X of Castile]]; a part of the manuscript is extant.{{sfn|Nallino|1987|pp=680{{ndash}}681}}

The {{transliteration|ar|zīj}} appears to have been widely used until the early 12th century. One 11th-century {{transliteration|ar|zīj}}, now lost, was compiled by al-Nasawī. That it was based on al-Battānī can be inferred from the matching values for the longitudes of the solar and planetary apogees. Al-Nasawī had as a young man written astronomical tables using data obtained from al-Battānī's {{transliteration|ar|zīj}}, but then discovered the data he used had been superseded by more accurately made calculations.<ref name="Moz">{{cite web |last1=Mozaffari |first1=S. Mohammad |title=The Orbital Elements of Venus in Medieval Islamic Astronomy: Interaction Between Traditions and the Accuracy of Observations |url=https://muslimheritage.com/the-orbital-elements-of-venus/ |website=Muslim Heritage |publisher=Foundation for Science, Technology and Civilisation, UK (FSTCUK) |access-date=23 January 2023 |archive-url=https://web.archive.org/web/20230123151131/https://muslimheritage.com/the-orbital-elements-of-venus/ |archive-date=23 January 2023 |date=2020}}</ref>

[[File:Al-Battani, Muhammad – De scientia stellarum frontispiece.jpg|thumb|The [[Book frontispiece|frontispiece]] of ''De scientia stellarum'' ([[Bologna]], 1645)]]
The invention of [[movable type]] in 1436 made it possible for astronomical works to be circulated more widely, and a [[Latin]] translation of the {{transliteration|ar|Kitāb az-Zīj aṣ-Ṣābi’}} was printed in [[Nuremberg]] in 1537 by the astronomer [[Regiomontanus]], which enabled Al-Battānī's observations to become accessible at the start of the scientific revolution in astronomy.{{sfn|Angelo|2014|p=79}}{{sfn|Kunitzsch|1974|p=115}} The {{transliteration|ar|zīj}} was reprinted in [[Bologna]] in 1645;{{sfn|Kunitzsch|1974|p=115}} the original document is preserved at the [[Vatican Library]] in Rome.<ref name="Dig">{{cite web |title=Manuscript – Vat.lat.3098 |url=https://digi.vatlib.it/mss/detail/122038 |website=DigiVatLib |publisher=[[Vatican Library]] |access-date=24 January 2023 |archive-date=24 January 2023 |archive-url=https://web.archive.org/web/20230124084924/https://digi.vatlib.it/mss/detail/122038 |url-status=live }}</ref>

The Latin translations, including the printed edition of 1537, made the {{transliteration|ar|zīj}} influential in the development of European astronomy.{{sfn|Kennedy|1956|pp=10{{ndash}}11}} A chapter of the {{transliteration|ar|Ṣābiʾ Zīj}} also appeared as a separate work, {{transliteration|ar|Kitāb Taḥqīq aqdār al-ittiṣālāt [bi-ḥasab ʿurūḍ al-kawākib]}} ("On the accurate determination of the quantities of conjunctions [according to the latitudes of the planets]").{{sfn|Van Dalen|2007}}

Al-Battānī's work was published in three volumes, in 1899, 1903, and 1907, by the Italian [[Oriental studies|Orientalist]] [[Carlo Alfonso Nallino]],{{sfn|Zamani|2014}} who gave it the title {{lang|la|Al-Battānī sive Albatenii opus astronomicum: ad fidem codicis Escurialensis Arabice editum}}. Nallino's edition, although in Latin, is the foundation of the modern study of medieval Islamic astronomy.{{sfn|Kennedy|1956|pp=10{{ndash}}11}}

==={{transliteration|ar|Maʻrifat Maṭāliʻi l-Burūj}}===
{{transliteration|ar|Kitāb maʿrifat maṭāliʿ al-burūd̲j̲ fī mā baina arbāʿ al-falak}} ({{lang|ar|معرفة مطالع البروج}}, “The book of the science of the ascensions of the signs of the zodiac in the spaces between the quadrants of the celestial sphere”){{sfn|Nallino|1987|pp=680{{ndash}}681}} may have been about calculations relating to the [[zodiac]]. The work is mentioned in a work by Ibn al-Nadim, and is probably identical with chapter 55 of al-Battānī's {{transliteration|ar|zīj}}. It provided methods of calculation needed in the astrological problem of finding {{transliteration|ar|al-tasyīr}} (directio).{{sfn|Van Dalen|2007}}

===Other works===
* {{transliteration|ar|Kitāb fī dalāʾil al-qirānāt wa-l-kushūfāt}} ("On the astrological indications of conjunctions and eclipses") is a treatise on [[horoscope]]s and astrology in connection with conjunctions of Saturn and Jupiter that occurred during the earliest period of Islam. The extant manuscript is held in the İsmail Saib Library at [[Ankara University]].{{sfn|Van Dalen|2007}}
* {{transliteration|ar|Sharḥ kitāb al-arbaʿa li-Baṭlamiyūs}} ({{lang|ar|شرح كتاب الأربع مقالات في أحكام علم النجوم
}}, "Commentary on Ptolemy's Tetrabiblos") is a commentary on the {{transliteration|ar|Kitāb al-Arbaʿ maqālāt}} in the version of [[Abu as-Salt]]. Al-Battānī mentions two earlier treatises that are likely identical to two chapters of the {{transliteration|ar|Ṣābiʾ Zīj}}.<ref name="Loh">{{cite web |last1=Löhr |first1=Nadine |title=al-Battānī, Sharḥ Kitāb al-Arbaʿ maqālāt fī aḥkām ʿilm al-nujūm |url=https://ptolemaeus.badw.de/work/193 |website=Ptolemaeus Arabus et Latinus |access-date=23 January 2023 |archive-date=23 January 2023 |archive-url=https://web.archive.org/web/20230123080828/https://ptolemaeus.badw.de/work/193 |url-status=live }}</ref> It is extant in the manuscripts Berlin Spr. 1840 (Ahlwardt #5875) and Escorial árabe 969/2.{{sfn|Van Dalen|2007}}
* {{transliteration|ar|Arbaʻ maqālāt}} ({{lang|ar|أربع مقالات}}, "Four discourses") was a commentary on Ptolemy's {{lang|la|Quadripartitum de apotelesmatibus e judiciis astrorum}}, known as the {{lang|el|[[Tetrabiblos]]}}.{{sfn|Khallikān (ibn)|1868|pp=318, 320}} The 10th-century encyclopedist [[Ibn Nadim]] in his {{transliteration|ar|[[al-Fihrist|Kitāb al-Fihrist]]}}, lists al-Battānī among a number of authors of commentaries on this work.{{sfn|Van Dalen|2007}}{{sfn|Nadīm (al-)|1899|p=640}}{{Efn|Ptolemy's treatise was translated into Arabic by [[Abu al-Salt|Ibrahim ibn al-Salt]] and this translation was amended by [[Hunayn ibn Ishaq]].<sup>''cite''</sup>}}
*{{transliteration|ar|Maʻrifat maṭāliʻ al-burūj}} ({{lang|ar|معرفة مطالع البروج}}, "Knowledge of the rising-places of the zodiacal signs").{{sfn|Khallikān (ibn)|1868|p=317}}
* {{transliteration|ar|Kitāb fī miqdār al-ittiṣālāt}} ({{lang|ar|كتاب في مقدار الاتصالات}}), an astrological treatise on the four "quarters of the sphere".{{sfn|Khallikān (ibn)|1868|p=317}}

== Legacy ==
===Medieval period===
The {{transliteration|ar|al-Zīj al-Ṣābī}} was renowned by medieval Islamic astronomers; the Arab polymath [[al-Bīrūnī]] wrote {{transliteration|ar|Jalā' al-adhhān fī zīj al-Battānī}} ("Elucidation of genius in al-Battānī's Zīj"), now lost.{{sfn|Van Dalen|2007}}

Al-Battānī's work was instrumental in the development of science and astronomy in the west.<ref name="OCoRob" /> Once it became known, it was used by medieval European astronomers and during the Renaissance.{{sfn|Van Dalen|2007}} He influenced Jewish [[rabbi]]s and philosophers such as [[Abraham ibn Ezra]] and [[Gersonides]].<ref name="Gal" /> The 12th-century scholar [[Maimonides|Moses Maimonides]], the intellectual leader of medieval Judaism, closely followed al-Battānī.{{sfn|Ronan|1983|p=211}} [[Hebrew language|Hebrew]] editions of the {{transliteration|ar|al-Zīj al-Ṣābī}} were produced by the 12th-century [[Catalans|Catalan]] astronomer [[Abraham bar Hiyya]] and the 14th-century French mathematician [[Immanuel Bonfils]].{{sfn|Van Dalen|2007}}

Copernicus referred to "al-Battani the Harranite" when discussing the orbits of Mercury and Venus. He compared to his own value for the sidereal year with those obtained by al-Battānī, Ptolemy and a value he attributed to the 9th-century scholar [[Thabit ibn Qurra]].{{sfn|Freely|2010|p=61}} The accuracy of al-Battānī's observations encouraged Copernicus to pursue his ideas about the [[Heliocentrism|heliocentric]] nature of the cosmos,{{sfn|Angelo|2014|p=78}} and in the book that initiated the [[Copernican Revolution]], the {{lang|la|[[De Revolutionibus Orbium Coelestium]]}}, al-Battānī is mentioned 23 times.{{sfn|Hoskin|1999|p=58}}

===16th and 17th centuries===
Al-Battānī's tables were used by the German mathematician [[Christopher Clavius]] in reforming the [[Julian calendar]], leading to it being replaced by the [[Gregorian calendar]] in 1582.{{sfn|Angelo |2014|p=79}} The astronomers [[Tycho Brahe]], [[Giovanni Battista Riccioli]], [[Johannes Kepler]] and [[Galileo Galilei]] cited Al-Battānī or his observations.<ref name="OCoRob"/> His almost exactly correct value obtained for the Sun's [[orbital eccentricity|eccentricity]] is better than the values determined by both Copernicus and Brahe.{{sfn|Van Dalen|2007}}

The [[Lunar craters|lunar crater]] [[Albategnius (crater)|Albategnius]] was named in his honour during the 17th century. Like many of the craters on the Moon's near side, it was given its name by Riccioli, whose 1651 [[nomenclature]] system has become standardized.{{sfn|Whitaker|1999|p=61}}

In the 1690s, the English [[physicist]] and astronomer [[Edmund Halley]], using Plato Tiburtius's translation of al-Battānī's {{transliteration|ar|zīj}}, discovered that the Moon's speed was possibly increasing.{{sfn|Cook|1998|pp=225{{ndash}}227}} Halley researched the location of Raqqa, where al-Battānī's observatory had been built, using the astronomer's calculations for the solar obliquity, the interval between successive autumnal equinoxes and several solar and lunar eclipses seen from Raqqa and Antioch. From this information, Halley derived the mean motion and position of the Moon for the years 881, 882, 883, 891, and 901. To interpret his results, Halley was dependent upon on knowing the location of Raqqa, which he was able to do once he had corrected the accepted value for the latitude of [[Aleppo]].{{sfn|Cook|1998|p=226}}

===18th century – present===
Al-Battānī's observations of eclipses were used by the English astronomer [[Richard Dunthorne]] to determine a value for the increasing speed of [[Orbit of the Moon|the Moon in its orbit]], he calculated that the lunar longitude was changing at a rate of 10 [[Minute and second of arc|arcseconds]] per century.{{sfn|Van Dalen|2007}}{{sfn|North|1994|p=389}}

Al-Battānī's data is still used by [[Geophysics|geophysicists]].{{sfn|Dalmau|1997}}

== Notes ==
{{Notelist}}

== References ==
{{Reflist}}

==Sources==
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*{{cite book|last=Khallikān (ibn)|author-link=Ibn Khallikan|first=Aḥmad i. M| title=Wafayāt al-A'yān wa Anbā' (Ibn Khallian's Biographical Dictionary) |editor-last=[[William McGuckin de Slane|Mac Guckin de Slane]] |editor-first=William |place=Paris & London| publisher=W.H. Allen |year=1868|volume=III|page=317|url=https://archive.org/stream/WafayatAl-ayantheObituariesOfEminentMenByIbnKhallikan/Vol3Of4WafayatAl-ayantheObituariesOfEminentMenByIbnKhallikan#page/n319/mode/2up}}
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* {{cite book |last1=McLeod |first1=Alexus |title=Astronomy in the Ancient World: Early and Modern Views on Celestial Events |date=2016 |publisher=Springer International Publishing |location=Berlin |isbn=978-33192-3-600-1 |url=https://books.google.com/books?id=NuJ6DAAAQBAJ}}
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* {{cite book |last1=North |first1=John |title=The Norton History of Astronomy and Cosmology |date=1994 |publisher=W.W. Norton |location=New York |isbn=978-0-393-31193-8 |url=https://archive.org/details/nortonhistoryofa0000nort_v8n6/page/n7/mode/2up?q= |url-access=registration}}
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===Versions of {{transliteration|ar|Kitāb az-Zīj aṣ-Ṣābi’}}===
===={{transliteration|ar|Kitāb az-Zīj aṣ-Ṣābi’}} manuscripts====
* {{circa|1245{{ndash}}1250}} – [[Gerard of Abbeville]] [https://gallica.bnf.fr/ark:/12148/btv1b90768493 Manuscript: Latin 16657] ({{lang|la|Liber Albategni. – Almagesti minoris libri VI. – Tabule stellarum fixarum}})
* 1376{{ndash}}1475 – [https://digi.vatlib.it/mss/detail/122038 Manuscript:Vat.lat.3098] ({{lang|la|De Scientia stellarum (opus astronomicum) – Interpretatio latina Platonis Tiburtini. Praeit interpretis praefatio}})
* 14th century – [https://archivesetmanuscrits.bnf.fr/ark:/12148/cc66456r Manuscript Latin 7266] ({{lang|la|Opusculum cujus titulus : liber Machometi, filii Gebir, filii Cinem, qui vocatur Albateni, in numeris stellarum et in locis motuum earum, experimenti ratione conceptorum : interprete Platone Tiburtino}})

====19th, 20th century publications====
*{{cite book|last=Battani (al-)|first=Muḥammad ibn Jabir| title= Al-Battānī sive Albatenii opus astronomicum: ad fidem codicis Escurialensis Arabice editum (Kitāb Zīj al-Ṣābī')|editor-last=[[Carlo Alfonso Nallino|Nallino]]|editor-first=Carlo Alfonso |place=Milan |publisher= Mediolani Insubrum: Prostat apud Urlichum Hoeplium|year=1899|language=ar |volume=3|isbn=978-88-88097-26-8|url=https://archive.org/details/albattnsivealbat03battuoft|ref=none}}
*{{cite book|last=Battani (al-)|first=Muḥammad ibn Jabir| title= Al-Battānī sive Albatenii opus astronomicum: ad fidem codicis Escurialensis Arabice editum (Kitāb Zīj al-Ṣābī')|editor-last=[[Carlo Alfonso Nallino|Nallino]]|editor-first=Carlo Alfonso |place=Milan |publisher= Mediolani Insubrum: Prostat apud Urlichum Hoeplium|year=1903|language=ar |volume=1|isbn=978-88-88097-26-8|ref=none}}
*{{cite book|last=Battani (al-)|first=Muḥammad ibn Jabir| title= Al-Battānī sive Albatenii opus astronomicum: ad fidem codicis Escurialensis Arabice editum (Kitāb Zīj al-Ṣābī')|editor-last=[[Carlo Alfonso Nallino|Nallino]]|editor-first=Carlo Alfonso |place=Milan |publisher= Mediolani Insubrum: Prostat apud Urlichum Hoeplium|year=1907|language=ar |volume=2|isbn=978-88-88097-26-8|ref=none}}

==Further reading==
{{Commons category}}

* {{cite book |last1=Sarton |first1=George |author1-link=George Sarton |title=A History of Science: Ancient Science Through the Golden Age of Greece |date=1960 |publisher=[[Harvard University Press]] |location=Cambridge, Massachusetts |isbn=|oclc=179869164 |page=|url-access=registration |url=https://archive.org/details/historyofscience0001sart |ref=none |chapter=|volume=1}}

{{Islamic astronomy}}
{{Islamic mathematics}}

{{Authority control}}

{{DEFAULTSORT:Battani}}
[[Category:929 deaths]]
[[Category:Year of birth uncertain]]
[[Category:9th-century Arab people]]
[[Category:10th-century Arab people]]
[[Category:9th-century astrologers]]
[[Category:9th-century astronomers]]
[[Category:9th-century mathematicians]]
[[Category:9th-century people from the Abbasid Caliphate]]
[[Category:10th-century astrologers]]
[[Category:10th-century astronomers]]
[[Category:10th-century mathematicians]]
[[Category:Astronomers from the Abbasid Caliphate]]
[[Category:Astrologers of the medieval Islamic world]]
[[Category:People from Harran]]
[[Category:Scientists who worked on qibla determination]]
[[Category:Mathematicians from the Abbasid Caliphate]]
[[Category:Sabian scholars from the Abbasid Caliphate]]
[[Category:Equinoxes]]