(868-929 C.E.) Al Battani (ALBATEGNIUS)

(868-929 C.E.)   Al Battani (ALBATEGNIUS)  [

 Al Battani Abu Abdillah   *(Abu Abdullah Al-Battani)

* Matematika, Astronomi, Insinyur , mathematics]

Al–Battani

Abū ʿAbd Allāh Muḥammad ibn Jābir ibn Sinān al-Raqqī al-Ḥarrānī al-Ṣābiʾ al-Battānī (Arabic: محمد بن جابر بن سنان البتاني) (Latinized as Albategnius, Albategni or Albatenius) (c. 858 – 929) was an Arab astronomer, astrologer, and mathematician. He introduced a number of trigonometric relations, and his Kitāb az-Zīj was frequently quoted by many medieval astronomers, including Copernicus.[1]

Born      c. 858 CE

Harran, Bilad al-Sham

Died       929 CE

Qasr al-Jiss, near Samarra

Era          Islamic Golden Age

Region  Caliphate

Main interests

Mathematics, Astronomy, Astrology

Notable ideas

Trigonometrical relationships

Major works   Kitāb az-Zīj

Little is known about al-Battānī's life beside that he was born in Harran near Urfa, in syria Upper Mesopotamia, which is now in Turkey, and his father was a famous maker of scientific instruments.[1] His epithet aṣ-Ṣabi’ suggests that among his ancestry were members of the Sabian sect; however, his full name indicates that he was Muslim.[2] Some western historians state that he is of noble origin, like an Arab prince,[3] but traditional Arabic biographers make no mention of this.[1] He lived and worked in ar-Raqqah, a city in north central Syria.

Astronomy

One of al-Battānī's best-known achievements in astronomy was the determination of the solar year as being 365 days, 5 hours, 46 minutes and 24 seconds.[2]

He was able to correct some of Ptolemy's results and compiled new tables of the Sun and Moon, long accepted as authoritative.[3] Some of his measurements were even more accurate than ones taken by Copernicus many centuries later. Researchers have ascribed this phenomenon to al-Battānī being in a geographical location that is closer to the southern latitude, which might have been more favorable for such observations.[2]

Al-Battānī discovered that the direction of the Sun's apogee, as recorded by Ptolemy, was changing.[4] (In modern heliocentric terms this is due to the changing direction of the eccentricity vector of the Earth's orbit). He also introduced, probably independently of the 5th century Indian astronomer Aryabhata, the use of sines in calculation, and partially that of tangents.[3] He also calculated the values for the precession of the equinoxes (54.5" per year, or 1° in 66 years) and the obliquity of the ecliptic (23° 35').[2] He used a uniform rate for precession in his tables, choosing not to adopt the theory of trepidation attributed to his colleague Thabit ibn Qurra.

Al-Battānī's work is considered instrumental in the development of science and astronomy.[2] Copernicus quoted him in the book that initiated the Copernican Revolution, the De Revolutionibus Orbium Coelestium. Al-Battānī was frequently quoted by Tycho Brahe, Riccioli, among others. Kepler and Galileo showed interest in some of his observations,[1] and his data continues to be used in geophysics.[5]

Mathematics

In mathematics, al-Battānī produced a number of trigonometrical relationships:

He also solved the equation sin x = a cos x discovering the formula:

He gives other trigonometric formulae for right angled triangles such as:[2]

Al-Battānī used al-Marwazi's idea of tangents ("shadows") to develop equations for calculating tangents and cotangents, compiling tables of them. He also discovered the reciprocal functions of secant and cosecant, and produced the first table of cosecants, which he referred to as a "table of shadows" (in reference to the shadow of a gnomon), for each degree from 1° to 90°.[6]

Works

Al-Battānī's major work is Kitāb az-Zīj ("Book of Astronomical Tables"). It was largely based on Ptolemy's theory, and other Greco-Syriac sources, while showing little Indian or Persian influence.[1][7] In his zij, he provided descriptions of a quadrant instrument.[8]

This book went through many translations to Latin and Spanish, including a Latin translation as De Motu Stellarum by Plato of Tivoli in 1116, which was later reprinted with annotations by Regiomontanus.[3] A reprint appeared at Bologna in 1645. The original MS. is preserved at the Vatican; and the Escorial library possesses in MS. a treatise of some value by him on astronomical chronology.[3]

Sejumlah karya tentang astronomi islam terlahir dari buah pikirnya. Salah satu karyanya yang paling populer adalah al-Zij al-Sabi. Kitab itu sangat bernilai dan dijadikan rujukan para ahli astronomi Barat selama beberapa abad, selepas Al-Battani meninggal dunia. Ia berhasil menentukan perkiraan awal bulan baru, perkiraan panjang matahari, dan mengoreksi hasil kerja Ptolemeus mengenai orbit bulan dan planet-planet tertentu. Al-Battani juga mengembangkan metode untuk menghitung gerakan dan orbit planet-planet. Ia memiliki peran yang utama dalam merenovasi astronomi modern yang berkembang kemudian di Eropa.

Al–Battani

One of the most important astronomers and mathematicians of this time in either the Eastern or the Western world was al–Battani (c. 858–929), whose full name was Abu Abdallah Muhammad ibn Jabir ibn Sinan al–Raqqi al–Harrani al–Sabi al–Battani

As in other branches of science and mathematics, figures from the Arab world made key contributions in astronomy during the period of time that Europeans refer to as the Middle Ages. Many of these Arab investigators were fully aware of the fund of scientific knowledge that had come down from the Greeks and Romans of antiquity, and in many cases they improved on the principles and observations they had inherited. Al–Battani's work grew to a position of renown among European astronomers in later centuries, among whom he was known under various Latin (or Italian) forms of his name: Albatenius, Albategnius, or Albategni. His estimates of the length of the year, and of other less familiar numerical underpinnings of the modern science of astronomy, turned out to be strikingly accurate in an age that knew no telescopes or other modern astronomical equipment. He is regarded as one of the greatest astronomers in the entire tradition of the Islamic world.

Family Worshipped Stars

The facts of al–Battani's life are known only in outline. Based on the 877 date that he himself attached to his earliest astronomical observations, he is believed to have been born in the decade of the 850s in the European calendar, perhaps in the year 858. He was a native of Harran, in what is now Turkey, southeast of the modern city of Urfa. At the time, the area was part of the Mesopotamian lands whose cultural and administrative center was Baghdad. Although the "Abdallah Muhammad" component of his full name indicates that he converted to the Islamic faith at some point, his family adhered to the Sabian religion, a local sect in whose belief system the stars played a central role. Members of this sect had transmitted and cultivated astronomical data and stories dating back to the culture of ancient Mesopotamia, centuries before. The area spawned other important astronomers and mathematicians including Thabit ibn Qurra, who was slightly older than al–Battani and would have lived in Harran during al–Battani's youth.

It is unclear where al–Battani acquired that name; it might have referred to a place where he lived or worked later in life. The "al–Harrani" ("Resident of Harran") portion of his name was shared with another famous scientific figure of the time, Jabir ibn Sinan al–Harrani, who was a maker of scientific instruments and who may well have been al–Battani's father. Al–Battani himself was noted for his skill in this trade, and some of the accuracy of the measurements for which he became famous was due to the superior quality of the instruments he made for himself. Among these was an ingenious type of astronomical model called an armillary sphere; mounted like a modern globe, it contained rings representing the movements of celestial bodies. Like a globe, the hollow sphere could be rotated on a central axis, and the individual rings could also be rotated. The whole sphere was encircled by a larger ring whose circumference was divided into degrees.

Al–Battani did not invent the armillary sphere, but his sphere was more precise than earlier versions. Modeling of this kind helped al–Battani make several important astronomical calculations regarding the sun's relationship to the earth. Although the realization that the earth orbited around the sun rather than the other way around awaited the discoveries of Copernicus, published in 1543, al–Battani accurately observed that the distance between sun and earth varies rather than remaining constant. One correct conclusion al–Battani drew from this observation was that annular eclipses of the sun, in which the moon interposes itself exactly between earth and sun but leaves a bright ring around its edge, would occur occasionally, when the sun was at its greatest distance from the earth.

Another important and accurate observation al–Battani made regarding the earth and sun pertained to the fact that the plane formed by the earth–sun orbit does not match that formed by an imaginary slice through the earth's equator. Al–Battani's calculation of the angle between these two planes, known as the obliquity or inclination of the ecliptic, resulted in the figure of 23 degrees and 35 minutes, remarkably close to the actual figure of 23 degrees, 27 minutes, and 8.26 seconds. He also made important discoveries concerning the so–called precession of the equinoxes, the changes in the time of the annual equinox as reckoned against the positions of bodies in the sky. All of this information was well known to the European astronomers of the Renaissance who laid the foundations for the modern understanding of the physical world.

Lived in Present – Day Syria

Al–Battani apparently spent much of the roughly 40 years of his astronomical career in the city of al–Raqqa, on the Euphrates River in what is now Syria (hence the "al–Raqqi" in his name). He may have chosen that place because several other families from Harran had moved there. Much of his time was spent in making astronomical observations and in compiling the data that underlay his major work, known as the Kitab al–Zij (The Book of Astronomy) or simply as the Zij (a word originally derived from the Persian language, where it denoted a certain strand used in weaving a rug. After issuing the Zij in one version before the year 900, he revised it sometime after 901, taking into account two eclipses, one solar and one lunar, that he had had the chance to see that year on a visit to the city of Antioch in Syria.

The Zij had 57 chapters, plus a preface in which al–Battani exhorted future generations to improve upon his own results. It ranged widely over what was known in his time of the heavens and the structure of the universe. The first part of the book described the celestial sphere and divided it in two ways, into degrees and into signs of the Zodiac—in the ancient world, astrology was considered an important and fully valid science, and several of al–Battani's shorter writings took up aspects of the subject. Al–Battani went on to lay out the mathematical underpinnings of his work, and then to take up specific astronomical problems.

Along the way he included a catalogue of stars that he had made in the year 880, naming 489 stars and creating one of the most valuable star registries of the era before telescopes (although the Greek astronomer Ptolemy had named 1,022). He also estimated the length of the year at 365 days, 5 hours, 48 minutes, and 24 seconds, an error of slightly less than seven one–hundredths of one percent. In the middle of the book, al–Battani explained his theory of the motion of the sun, the moon, and the five known planets (Mercury, Venus, Mars, Jupiter, and Saturn). He gave directions for using the tables in the book, returned to astrology toward the end, and concluded the book with several chapters on the construction of astronomical instruments, including a sundial. The Arab bookseller Ibn an–Nadim, writing in the year 988 (and quoted in a review of al–Battani's work shown on the website of St. Andrews University of Scotland) opined that "Nobody is known in Islam who reached similar perfection in observing the stars and scrutinizing their motions."

Several other specific aspects of al–Battani's work exerted a strong influence over later generations of scholars. The most important was that he used what we would now call trigonometry—the study of the ratios pertaining to the sides and angles of right triangles—in making his calculations. Trigonometry had roots in ancient India and spread from there to the Arab world. Al–Battani made use of such concepts as the sine, cosine, tangent, and cotangent, an improvement over the methods used by the greatest of the Greek astronomers, Ptolemy.

Ptolemy (active beginning around the year 127) was widely revered by Arab astronomers of the day, including al–Battani. In fact, just as younger scholars today may be reluctant to dismantle the work of their mentors, al–Battani was circumspect about criticizing Ptolemy even where he had clearly improved on the Greek astronomer's work. He tended rather to correct Ptolemy in a tacit way, without referring to Ptolemy's errors. In general, al–Battani's place in history is that of a refiner of Ptolemy's investigations.

Died after Petitioning Baghdad Government

Al–Battani was active as an astronomer until about the year 918. In the year 929 he accompanied a group of townspeople from al–Raqqa, who may have included some of his own descendants, to Baghdad as part of what was likely a tax protest. The aging astronomer survived to plead his cause but died on the journey home at Qasr al–Jiss, near the present–day Iraqi city of Samarra.

After his death, al–Battani's influence was magnified. The praise of the bookseller Ibn an–Nadim cited above attests to his fame in the Arab world. During the later medieval era in Europe, Western scholars turned to the Islamic world as they attempted to reconstruct the foundations of sciences that had been buried since the decline of the Roman empire centuries before. Not only astronomy and mathematics but also music, medicine, history, and linguistic studies in the West bear strong Arabic imprints at their deepest levels. Al–Battani's Zij was twice translated into Latin in the twelfth century, but only one translation, made by Plato of Tivoli in 1116 under the title De motu stellarum (On the Motion of the Stars), survived. The lost translation was by one Robert Retinensis, probably Robert of Chester, the first scholar to translate the Koran into Latin. King Alfonso X of Spain ordered another translation made in the thirteenth century, this one into Spanish. This also survives today. Al–Battani's original manuscript is housed in the Vatican Library.

At a time when very few books were selected to appear in printed form, al–Battani's Zij made the list. The translation by Plato of Tivoli was published in Nürnberg, Germany, in 1537 and another edition appeared in Bologna, Italy, in 1645. Thus the treatise became known to astronomers and mathematicians all over central and northern Europe. Spanish Jewish astronomers, too, knew al–Battani's work. The greatest astronomers of the European Renaissance—Nicholas Copernicus, Johannes Kepler, and Tycho Brahe—all explicitly acknowledged al-Battani's influence, and as late as 1749 his observations of eclipses were still being cited by astronomers.

Al–Battani's observations of solar motion, in fact, were more accurate than those of the great Copernicus himself, perhaps because al–Battani worked at a more southerly latitude and did not have to factor into his calculations certain types of atmospheric refraction that become more pronounced closer to the poles. The European historian of Islam C.A. Nallino published a gigantic Arabic edition of al–Battani's Zij in three volumes between 1899 and 1907, and science historians since then have noted his role as a follower of Ptolemy and as a bridge–builder between the ancient world and the foundations of modern astronomy. Like much of the fascinating history of the Arab world's influence on Western science and culture, however, al–Battani's name is little known even among general readers with a scientific background in Western countries.

Books

Biographical Dictionary of Mathematicians, edited by Charles Coulston Gillispie, Scribner's, 1991.

Daintith, John, et al., Biographical Encyclopedia of Scientists, 2nd. ed., Institute of Physics Publishing, 1994.

Encyclopedia of the Institute of Physics Publishing, 2nd. ed., 1994. edited by H.A.R. Gibb et al., Brill (Leiden, Netherlands), 1960.

Notable Mathematicians, Gale, 1998.

Sarton, George, Introduction to the History of Science, Volume I: From Homer to Omar Khayyam, Robert E. Krieger Publishing Company, 1975.

Online

"Abu Abdallah Mohammad ibn Jabir Al–Battani," School of Mathematics and Statistics, University of St. Andrews, Scotland, http://www–gap.dcs.st–and.ac.uk (December 13, 2004).

Al-Battani adalah seorang astrolog dan metimatikawan asal Suriah yangmemiliki nama lengkap Abu Abdallah Muhammad Ibn Jabir Ibn Sinan Al-Battani.Atau kadang dikenal Albategnius, Albategni atau Albatenius dalam bahasalatinnya. Al Battani lahir di Battan, Harran, Suriah pada sekitar 858 M.Keluarganya merupakan penganut sekte Sabbian yang melakukan ritualpenyembahan terhadap bintang. Menjadi penyembah bintang-bintang berartibahwa Sabiian memiliki motivasi yang kuat bagi studi astronomi dan merekamenghasilkan banyak astronom dan hebat matematika seperti Thabit bin Qurra.tidak seperti Tsabit, Al-Battani tidak percaya pada agama Sabian. ia lebihmemilih memeluk Islam. Ketertarikannya dengan benda-benda yang ada di langit membuat AlBattani kemudian menekuni astronomi. Secara informal ia mendapatkanpendidikan dari ayahnya yang juga seorang ilmuwan, Jabir Ibn San’an Al-Battani.Ayahmya adalah seorang pembuat instrument terkenal di Harran. Sehinggakemampuan Al-Battani dalam membuat instrument sudah tidak diragukan lagi.Keyakinan ini menguat dengan adanya bukti kemampuan Al Battani membuat danmenggunakan sejumlah perangkat alat astronomi seperti yang dilakukan ayahnya. Beberapa saat kemudian, ia meninggalkan Harran menuju Raqqa yangterletak di tepi Sungai Eufrat, di sana ia melanjutkan pendidikannya. Di kotainilah ia melakukan beragam penelitian hingga ia menemukan berbagai penemuancemerlangnya. Pada saat itu, Raqqa menjadi terkenal dan mencapai kejayaan. Raqqa menjadi terkenal dan mencapai kemakmuran. Ini disebabkan karenakalifah Harun Al Rashid, khalifah kelima dalam dinasti Abbasiyah, pada 14September 786 membangun sejumlah istana di kota tersebut. Ini merupakanpenghargaan atas sejumlah penemuan yang dihasilkan oleh penelitian yangdilakukan Al Battani. Usai pembangunan sejumlah istana di Raqqa, kota inimenjadi pusat kegiatan baik ilmu pengetahuan maupun perniagaan yang ramai.

7. Kritik: bagian ini menjelaskan tentang identitas dari Al-Battani baik kota kelahiran, agama maupun keluarganya. Al-Battani begitu mahir dalam membuat dan memakai alat-alat astronomi karena didikan ayahnya langsung yang merupakan pembuat alat-alat yang terkenal pada saat itu. Ketertarikan Al- Battani terhadap astronomi diyakini karena agama keluarganya yang mengajarkan menyembah bintang. Di kota Raqqa ia melakukan beragam penelitian hingga ia menemukan berbagai penemuan cemerlangnya dan terkenal disana.ISI /HASIL Buah pikirnya dalam bidang astronomi yang mendapatkan pengakuandunia adalah lamanya bumi mengelilingi matahari. Berdasarkan perhitungannya,ia menyatakan bahwa bumi mengelilingi pusat tata surya tersebut dalam waktu365 hari, 5 jam, 46 menit, dan 24 detik. Perhitungannya mendekati denganperhitungan terakhir yang dianggap lebih akurat. Itulah hasil jerih payahnyaselama 42 tahun melakukan penelitian yang diawali pada masa mudanya diRaqqa, Suriah. Ia menemukan bahwa garis bujur terajauh matahari mengalamipeningkatan sebesar 16,47 derajat sejak perhitungan yang dilakukan olehPtolemy. Ini membuahkan penemuan yang penting mengenai gerak lengkungmatahari. Al Battani juga menentukan secara akurat kemiringin ekliptik, panjangnyamusim, dan orbit matahari. Ia pun bahkan berhasil menemukan orbit bulan danplanet dan menetapkan teori baru untuk menentukan sebuah kondisi kemungkinanterlihatnya bulan baru. Ini terkait dengan pergantian dari sebuah bulan ke bulanlainnya. Penemuannya mengenai garis lengkung bulan dan matahari, pada 1749kemudian digunakan oleh Dunthorne untuk menentukan gerak akselerasi bulan.

8. Layaknya, ilmuwan Muslim lainnya, ia pun menuliskan pengetahuannyadi kedua bidang itu ke dalam sejumlah buku. Bukunya tentang astronomi yangpaling terkenal adalah Kitab Al Zij. Buku ini diterjemahkan ke dalam bahasaLatin pada abad ke-12 dengan judul De Scienta Stellerum u De NumerisStellerum et Motibus oleh Plato dari Tivoli. Terjemahan tertua dari karyanya itumasih ada di Vatikan. Terjemahan buku tersebut tak semua dalam bahasa latintetapi juga bahasa lainnya. Terjemahan ini keluar pada 1116 sedangkan edisi cetaknya beredar pada1537 dan pada 1645. Sementara terjemahan karya tersebut ke dalam bahasaSpanyol muncul pada abad ke-13. Pada masa selanjutnya baik terjemahan karyaAl Battani dalam bahasa Latin maupun Spanyol tetap bertahan dan digunakansecara luas. Tak heran bila tulisannya, sangat memberikan pengaruh bagiperkembangan ilmu pengetahuan di Eropa hingga datangnya masa Pencerahan.Dalam Fihrist, yang dikompilasi Ibn An-Nadim pada 988, karya ini merupakankumpulan Muslim berpengaruh pada abad ke-10, dinyatakan bahwa Al Battanimerupakan ahli astronomi yang memberikan gambaran akurat mengenai bulandan matahari. Dalam bidang matematika, Al Battani juga memberikan kontribusigemilang terutama dalam trigonometri. Al Battani menemukan sejumlahpersamaan trigonometri:Beliau juga memecahkan persamaan sin x = a cos x dan menemukan rumus:

9. dan menggunakan gagasan al-Marwazi tentang tangen dalam mengembangkanpersamaan-persamaan untuk menghitung tangen, cotangen dan menyusun tabelperhitungan tangen. Informasi lain yang tertuang dalam Fihrist menyatakan pula bahwa AlBattani melakukan penelitian antara tahun 877 dan 918. Tak hanya itu, didalamnya juga termuat informasi mengenai akhir hidup sang ilmuwan ini. Fihristmenyatakan bahwa Al Battani meninggal dunia dalam sebuah perjalanan dariRaqqa ke Baghdad. Perjalanan ini dilakukan sebagai bentuk protes karena ia dikenai pajakyang berlebih. Al Battani memang mencapai Baghdad untuk menyampaikankeluhannya kepada pihak pemerintah. Namun kemudian ia menghembuskan nafasterakhirnya ketika dalam perjalanan pulang dari Baghdad ke Raqqa.Kritik:Pada bagian ini menceritakan bahwa banyak penemuan-penemuan Al-Battanidalam astonomi dan trigonometri. Bahkan perhitungan beliau sangat akurat.Berdasarkan perhitungannya, ia menyatakan bahwa bumi mengelilingi pusat tatasurya tersebut dalam waktu 365 hari, 5 jam, 46 menit, dan 24 detik.Perhitungannya mendekati dengan perhitungan terakhir yang dianggap lebihakurat. Adapun penemuan-penemuan lain Al-Battani yaitu:  Menemukan garis bujur terajauh matahari mengalami peningkatan sebesar 16,47 derajat sejak perhitungan yang dilakukan oleh Ptolemy. Al Battani menentukan secara akurat kemiringin ekliptik, panjangnya musim, dan orbit matahari  Ia berhasil menemukan orbit bulan dan planet dan menetapkan teori baru untuk menentukan sebuah kondisi kemungkinan terlihatnya bulan baru.  Dalam bidang matematika, Al Battani juga memberikan kontribusi gemilang terutama dalam trigonometri mengembangkan persamaan- persamaan untuk menghitung tangen, cotangen dan menyusun tabel perhitungan tangen.

10. KESIMPULAN Dari Artikel dapat disimpulkan bahwa: Al-Battani adalah seorang astrolog dan metimatikawan asal Suriah yang memiliki nama lengkap Abu Abdallah Muhammad Ibn Jabir Ibn Sinan Al- Battani Secara informal Al-Battani mendapatkan pendidikan dari ayahnya yang juga seorang ilmuwan, Jabir Ibn San’an Al-Battani Di kota Raqqa ia melakukan beragam penelitian hingga ia menemukan berbagai penemuan cemerlangnya dan terkenal Adapun buah karya Al-Battani yang terkenal ialah:  Keakuratan Al-Battani dalam menghitung lamanya bumi mengelilingi matahari 365 hari, 5 jam, 46 menit, dan 24 detik  Menemukan garis bujur terajauh matahari mengalami peningkatan sebesar 16,47 derajat sejak perhitungan yang dilakukan oleh Ptolemy. Ini membuahkan penemuan yang penting mengenai gerak lengkung matahari.  Al Battani menentukan secara akurat kemiringin ekliptik, panjangnya musim, dan orbit matahari  Ia berhasil menemukan orbit bulan dan planet dan menetapkan teori baru untuk menentukan sebuah kondisi kemungkinan terlihatnya bulan baru.  Dalam bidang matematika, Al Battani juga memberikan kontribusi gemilang terutama dalam trigonometri mengembangkan persamaan- persamaan untuk menghitung tangen, cotangen dan menyusun tabel perhitungan tangen. Bukunya tentang astronomi yang paling terkenal adalah Kitab Al Zij. Al Battani meninggal dunia dalam sebuah perjalanan dari Raqqa ke Baghdad.

11. Kritik:Pada bagian kesimpulan menceritakan tentang betapa panjang perjalanan tokohAl-Batani dan begitu banyak konstribusinya dalam bidang astronomi dantrigonometri. Al-Battani bisa dikatakan sebagai salah satu tokoh yangmenginspirasi pembuatan kalender karena dapat menemukan orbit bulan danplanet dan menetapkan teori baru untuk menentukan sebuah kondisi kemungkinanterlihatnya bulan baru. TUGAS 21. Mengapa anda memilih artikel tersebut? Jawab : Menurut saya artikel ini menarik, karena Al-Battani mampu menghitung lamanya bumi mengelilingi matahari dengan akurat. Selain itu Ia menemukan bahwa garis bujur terajauh matahari yang membuahkan penemuan yang penting mengenai gerak lengkung matahari. Beliau juga turut andil dalam menemukan kalender karena berhasil menemukan orbit bulan dan planet dan menetapkan teori baru untuk menentukan sebuah kondisi kemungkinan terlihatnya bulan baru. Ini terkait dengan pergantian dari sebuah bulan ke bulan lainnya. Selain itu, Penemuannya mengenai garis lengkung bulan dan matahari, pada 1749 kemudian digunakan oleh Dunthorne untuk menentukan gerak akselerasi bulan.2. Mengapa jurnal tersebut begitu penting? Jawab : jurnal ini begitu penting karena dengan jurnal ini kita mengetahui salah satu tokoh yang menginspirasi pembuatan kalender adalah Al-Battani karena beliau berhasil menemukan orbit bulan dan planet. Selain itu kita mengetahui tanpa Al-battani Dunthorne tidak bisa menentukan gerak akselerasi bulan

12. 3. Tuliskan 2 pokok pikiran yang Anda dapat dari membaca artikel tersebut! Jawab : Al-Battani adalah seorang astrolog dan metimatikawan asal Suriah yang memiliki nama lengkap Abu Abdallah Muhammad Ibn Jabir Ibn Sinan Al- Battani. Secara informal ia mendapatkan pendidikan dari ayahnya yang juga seorang ilmuwan, Jabir Ibn San’an Al-Battani. Ayahmya adalah seorang pembuat instrument terkenal di Harran. Di kota Raqqa ia melakukan beragam penelitian hingga ia menemukan berbagai penemuan cemerlangnya dan terkenalAdapun buah karya Al- Battani yang terkenal ialah:  Keakuratan Al-Battani dalam menghitung lamanya bumi mengelilingi matahari 365 hari, 5 jam, 46 menit, dan 24 detik  Menemukan garis bujur terajauh matahari mengalami peningkatan sebesar 16,47 derajat sejak perhitungan yang dilakukan oleh Ptolemy. Ini membuahkan penemuan yang penting mengenai gerak lengkung matahari.  Al Battani menentukan secara akurat kemiringin ekliptik, panjangnya musim, dan orbit matahari  Ia berhasil menemukan orbit bulan dan planet dan menetapkan teori baru untuk menentukan sebuah kondisi kemungkinan terlihatnya bulan baru.  Dalam bidang matematika, Al Battani juga memberikan kontribusi gemilang terutama dalam trigonometri mengembangkan persamaan- persamaan untuk menghitung tangen, cotangen dan menyusun tabel perhitungan tangen. Battani bisa menggunakan dan membuat alat astronomi sehingga dia dapat menghitung waktu bumi mengitari matahari

Al-Battani mendapat pendidikan dari ayahnya dan tetap melanjutkan pendidikannya. Al-Battani menerbitkan buku yang berjudul al-Zij yang diterjemahkan ke dalam bahasa Latin pada abad ke-12 dengan judul De Scienta Stellerum u De Numeris Stellerum et Motibus .Terjemahan tertua dari karyanya itu masih ada di Spanyol. Menurut Al-Battani bumi mengelilingi pusat tata surya dalam waktu A A. 365 hari, 5 jam, 46 menit, dan 24 detik penemuan-penemuan penting Al-Battani! Keakuratan Al-Battani dalam menghitung lamanya bumi mengelilingi matahari 365 hari, 5 jam, 46 menit, dan 24 detik Menemukan garis bujur terajauh matahari mengalami peningkatan sebesar 16,47 derajat sejak perhitungan yang dilakukan oleh Ptolemy. Ini membuahkan penemuan yang penting mengenai gerak lengkung matahari. Al Battani menentukan secara akurat kemiringin ekliptik, panjangnya musim, dan orbit matahari Ia berhasil menemukan orbit bulan dan planet dan menetapkan teori baru untuk menentukan sebuah kondisi kemungkinan terlihatnya bulan baru. Dalam bidang matematika, Al Battani juga memberikan kontribusi gemilang terutama dalam trigonometri mengembangkan persamaan- persamaan untuk menghitung tangen, cotangen dan menyusun tabel perhitungan tangen.

Abu Abdullah Al Battani, Sang Penemu Waktu dalam 1 Tahun

 “Dia-lah yang menjadikan matahari bersinar dan bulan bercahaya dan ditetapkan-Nya manzilah-manzilah (tempat-tempat) bagi perjalanan bulan itu, supaya kamu mengetahui bilangan tahun dan perhitungan (waktu). Allah tidak menciptakan yang demikian itu melainkan dengan hak. Dia menjelaskan tanda-tanda (kebesaran-Nya) kepada orang yang mengetahui.” (QS Yunus [10]: 5)

Ketepatan penghitungan al-Battani (850-932 M) dalam bidang astronomi, membuatnya berhasil menemukan perhitungan waktu dalam satu tahun yang terdiri dari 365 hari, 5 jam, 46 menit dan 24 detik.

Cendekiawan muslim di bidang astronomi dan matematika ini lebih dikenal di Barat dengan nama Albategnius. Beliau lahir di Battan, Suriah dengan nama lengkap Abu Abdullah Muhammad Ibnu Jabir Ibnu Sinan ar Raqqi al-Harrani as Sabi al-Battani.

Pemikirannya dalam bidang astronomi yang mendapat pengakuan dunia adalah penghitungan waktu bumi dalam mengelilingi pusat tata surya. Kerja kerasnya selama 42 tahun tersebut mendekati perhitungan terakhir yang dianggap lebih akurat.

Al Battani juga menentukan kemiringan ekliptik, panjangnya musim dan orbit matahari. Ia bahkan berhasil menemukan orbit bulan dan planet serta menetapkan teori baru dalam menentukan kemunculan bulan baru.

Penemuannya mengenai garis lengkung bulan dan matahari tersebut kemudian menjadi dasar bagi Dunthorne pada tahun 1749, untuk menentukan gerak akselerasi bulan.

Khalifah Harun al-Rashid membangun beberapa istana di kota Raqqa sebagai penghargaan atas sejumlah penemuan al-Battani yang kemudian mengantarkan kota ini mencapai kemakmuran dan menjadi pusat kegiatan ilmu pengetahuan.

Karya-karyanya di bidang astronomi sangat berpengaruh di Eropa hingga masa Renaisance. Salah satu bukunya yang paling terkenal, Kitab ‘al-Zij’ diterjemahkan ke dalam bahasa latin dengan judul ‘De Motu Stellarum’. Kitab inilah yang membuat Copernicus dalam bukunya ‘De Revolutuionibus Orbium Clestium’, mengungkapkan rasa hutang budinya kepada al-Battani.

Abu Abdallah Muhammad Ibn Jabir Ibn Sinan al-Battani al-Harrani was born around 858 C.E. in Harran, and according to one account, in Battan, a State of Harran. Battani was first educated by his father Jabir Ibn San'an al-Battani, who was also a well-known scientist. He then moved to Raqqa, situated on the bank of the Euphrates, where he received advanced education and later on flourished as a scholar. At the beginning of the 9th century, he migrated to Samarra, where he worked till the end of his life in 929 C.E. He was of Sabian origin, but was himself a Muslim. Al-Battani is sometimes known by a latinised version of his name, variants being Albategnius, Albategni or Albatenius. His full name was Abu Abdallah Mohammad ibn Jabir ibn Sinan al-Raqqi alHarrani al-Sabi al-Battani.  Al-Battani was born in Harran, called Carrhae in earlier times by the Romans, which lies on the Balikh River, 38 km southeast of Urfa. His family had been members of the Sabian sect, a religious sect of star worshippers from Harran. Being worshipers of the stars meant that the Sabians had a strong motivation for the study of astronomy and they produced many outstanding astronomers and mathematicians such as Thabit ibn Qurra. In fact Thabit was also born in Harran and would have still have been living there at the time that al-Battani was born. Al-Battani, unlike Thabit, was not a believer in the Sabian religion, however,

for "Abu Allah Mohammad" indicates that he was certainly a Muslim.

Although the identification is not absolutely certain, it is probable that al-Battani's father was Jabir ibn Sinan al-Harrani who had a high reputation as an instrument maker in Harran. The name certainly makes the identification fairly certain and the fact

that al-Battani himself was skilled in making astronomical instruments is a good indication that he learnt these skills from his father.

Al-Battani made his remarkably accurate astronomical observations at Antioch and ar-Raqqah in Syria. The town of arRaqqah, where most of al-Battani's observations were made, became prosperous when Harun al-Rashid, who became the fifth

Caliph of the Abbasid dynasty on 14 September 786, built several palaces there. The town had been renamed al-Rashid at that time but, by the time al-Battani began observing there, it had reverted to the name of ar-Raqqah. The town was on the Euphrates River just west of where it joins the Balikh River (on which Harran stands).  TheFihrist(Index) was a work compiled by the bookseller Ibn an-Nadim in 988. It gives a full account of the Arabic literature which was available in the 10th century and it describes briefly some of the authors of this literature. The Fihristdescribes alBattani as (see for example [1]):-

... one of the famous observers and a leader in geometry, theoretical and practical astronomy, and astrology. He composed a work on astronomy, with tables, containing his own observations of the sun and moon and a more accurate description of their motions than that given in Ptolemy's "Almagest". In it moreover, he gives the motions of the five planets, with the improved observations he succeeded in making, as well as other necessary astronomical calculations. Some of his observations mentioned in his book of tables were made in the year 880 and later on in the year 900.

Nobody is known in Islam who reached similar perfection in observing the stars and scrutinising their motions. Apart from this, he took great interest in astrology, which led him to write on this subject too: of his compositions in this field I mention his commentary on Ptolemy's Tetrabiblos.

Other information about al-Battani contained in the Fihristis that he observed between the years 877 and 918 and that his star catalogue is based on the year 880. It also describes the end of his

life which seems to have occurred during a journey he made to Baghdad to protest on behalf of a group of people from arRaqqah because they had been unfairly taxed. Al-Battani reached Baghdad and put his arguments but died on the return journey to ar-Raqqah.

The Fihristalso quotes a number of works by al-Battani.

There is his Kitab al-Zijwhich is his major work on astronomy with tables, referred to above. We shall examine this in more detail in a moment. There is also the commentary on Ptolemy's

Tetrabiblosreferred to above and two other titles: On ascensions of the signs of the zodiac and On the quantities of the astrological applications. One of the chapters of the Kitab al-Zijhas the title "On ascensions of the signs of the zodiac" and so the Fihrist may be wrong in thinking this is a separate work. This point still appears unclear.

Al-Battani's Kitab al-Zijis by far his most important work and we should examine briefly the topics which it covered. The work contained 57 chapters. It begins with a description of the division of the celestial sphere into the signs of the zodiac and into degrees. The necessary background mathematical tools are then introduced such as the arithmetical operations on sexagesimal

fractions and the trigonometric functions. Chapter 4 contains data from al-Battani's own observations. Chapters 5 to 26 discuss a large number of different astronomical problems following to some extent material from the Almagest. The motions of the sun, moon and five planets are discussed in chapters 27 to 31, where the theory given is that of Ptolemy but for al-Battani the theory appears less important than the practical aspects.

After giving results to allow data given for one era to be converted to another era, al-Battani then gives 16 chapters which

explain how his tables are to be read. Chapters 49 to 55 cover problems in astrology, while chapter 56 discusses the construction of a sundial and the final chapter discusses the construction of a number of astronomical instruments.

What are the main achievements of al-Battani's Zij? He catalogued 489 stars. He refined the existing values for the length of the year, which he gave as 365 days 5 hours 48 minutes 24 seconds, and of the seasons. He calculated 54.5" per year for the precession of the equinoxes and obtained the value of 23 35' for the inclination of the ecliptic.

Rather than using geometrical methods, as Ptolemy had done,

al-Battani used trigonometrical methods which were an important advance. For example he gives important trigonometric formulas for right angled triangles such as

bsin(A) = asin(90 - A).

Al-Battani showed that the farthest distance of the Sun fromthe Earth varies and, as a result, annular eclipses of the Sun are possible as well as total eclipses. However, as Swerdlow points out in [8], the influence of Ptolemy was remarkably strong on all medieval authors, and even a brilliant scientist like al-Battani probably did not dare to claim a different value of the distance from the Earth to the Sun from that given by Ptolemy. This was despite the fact that al-Battani could deduce a value for the distance from his own observations that differed greatly from Ptolemy's.

In [1] Hartner gives a somewhat different opinion of the way

that al-Battani is influenced by Ptolemy. He writes:-    While al-Battani takes no critical attitude towards the Ptolemaic kinematics in general, he evidences ... a very sound scepticism in regard to Ptolemy's practical results. Thus, relying on his own

observations, he corrects - be it tacitly, be it in open words -Ptolemy's errors. This concerns the main parameters of planetary motion no less than erroneous conclusions drawn from

insufficient or faulty observations, such as the invariability of the obliquity of the ecliptic or of the solar apogee.  Al-Battani is important in the development of science for a number of reasons, but one of these must be the large influence his work had on scientists such as Tycho Brahe, Kepler, Galileo and Copernicus. In [5] there is a discussion on how al-Battani managed to produce more accurate measurements of the motion of the sun than did Copernicus. The author suggests that alBattani obtained much more accurate results simply because his observations were made from a more southerly latitude. For alBattani refraction had little effect on his meridian observations at the winter solstice because, at his more southerly site of arRaqqah, the sun was higher in the sky.

Al-Battani's Kitab al-Zij was translated into Latin as De motu stellarum (On the motion of the stars) by Plato of Tivoli. This appeared in 1116 while a printed edition of Plato of Tivoi's translation appeared in 1537 and then again in 1645. A Spanish translation was made in the 13th century and both it and Plato of Tivoli's Latin translation have survived.

Reference:

1. Biography in Dictionary of Scientific Biography (New York 1970-1990).

2. Biography in Encyclopaedia Britannica.

3. Al-Battani, Encylopedia of Islam (Leiden, 1960).

4. P Kunitzsch, New light on al-Battani's Zij, Centaurus 18 (1973/74), 270-274.

5. Y Maeyama, Determination of the Sun's orbit (Hipparchus, Ptolemy, alBattani, Copernicus, Tycho Brahe), Arch. Hist. Exact Sci. 53 (1) (1998), 1-49.

6. K Maghout, al-Battani : un grand astronome et mathématicien arabe, Bull. Etudes Orient. 41(42) (1989/90), 55-58.

7. F J Ragep, Al-Battani, cosmology, and the early history of trepidation in Islam, in From Baghdad to Barcelona, Zaragoza, 1993 I, II (Barcelona, 1996), 267-298.

8. N Swerdlow, Al-Battani 's determination of the solar distance, Centaurus 17 (2) (1972), 97-105.