Al-Battani
Encyclopedia
Abū ʿAbd Allāh Muḥammad ibn Jābir ibn Sinān al-Raqqī al-Ḥarrānī al-Ṣābiʾ al-Battānī (Latinized as Albategnius, Albategni or Albatenius) (c. 858, Harran
Harran
Harran was a major ancient city in Upper Mesopotamia whose site is near the modern village of Altınbaşak, Turkey, 24 miles southeast of Şanlıurfa...

 – 929, Qasr al-Jiss, near Samarra
Samarra
Sāmarrā is a city in Iraq. It stands on the east bank of the Tigris in the Salah ad-Din Governorate, north of Baghdad and, in 2003, had an estimated population of 348,700....

) was a Muslim
Muslim
A Muslim, also spelled Moslem, is an adherent of Islam, a monotheistic, Abrahamic religion based on the Quran, which Muslims consider the verbatim word of God as revealed to prophet Muhammad. "Muslim" is the Arabic term for "submitter" .Muslims believe that God is one and incomparable...

 astronomer
Islamic astronomy
Islamic astronomy or Arabic astronomy comprises the astronomical developments made in the Islamic world, particularly during the Islamic Golden Age , and mostly written in the Arabic language. These developments mostly took place in the Middle East, Central Asia, Al-Andalus, and North Africa, and...

, astrologer, and mathematician
Islamic mathematics
In the history of mathematics, mathematics in medieval Islam, often termed Islamic mathematics or Arabic mathematics, covers the body of mathematics preserved and developed under the Islamic civilization between circa 622 and 1600...

. He introduced a number of trigonometric relations, and his Kitāb az-Zīj was frequently quoted by many medieval astronomers, including Copernicus.

Life

Little is known about al-Battānī's life beside that he was born in Harran
Harran
Harran was a major ancient city in Upper Mesopotamia whose site is near the modern village of Altınbaşak, Turkey, 24 miles southeast of Şanlıurfa...

 near Urfa, in Upper Mesopotamia
Mesopotamia
Mesopotamia is a toponym for the area of the Tigris–Euphrates river system, largely corresponding to modern-day Iraq, northeastern Syria, southeastern Turkey and southwestern Iran.Widely considered to be the cradle of civilization, Bronze Age Mesopotamia included Sumer and the...

, which is now in Turkey
Turkey
Turkey , known officially as the Republic of Turkey , is a Eurasian country located in Western Asia and in East Thrace in Southeastern Europe...

, and his father was a famous maker of scientific instruments. His epithet aṣ-Ṣabi’ suggests that among his ancestry were members of the Sabian
Sabians
The Sabians of Middle Eastern tradition were a monotheistic Abrahamic religious group mentioned three times in the Quran: "the Jews, the Sabians, and the Christians." In the Hadith they are nothing but converts to Islam, while their identity in later Islamic literature became a matter of...

 sect; however, his full name indicates that he was Muslim
Muslim
A Muslim, also spelled Moslem, is an adherent of Islam, a monotheistic, Abrahamic religion based on the Quran, which Muslims consider the verbatim word of God as revealed to prophet Muhammad. "Muslim" is the Arabic term for "submitter" .Muslims believe that God is one and incomparable...

. Some western historians state that he is of noble origin, like an Arab
Arab
Arab people, also known as Arabs , are a panethnicity primarily living in the Arab world, which is located in Western Asia and North Africa. They are identified as such on one or more of genealogical, linguistic, or cultural grounds, with tribal affiliations, and intra-tribal relationships playing...

 prince, but traditional Arabic biographers make no mention of this. He lived and worked in ar-Raqqah, a city in north central Syria
Syria
Syria , officially the Syrian Arab Republic , is a country in Western Asia, bordering Lebanon and the Mediterranean Sea to the West, Turkey to the north, Iraq to the east, Jordan to the south, and Israel to the southwest....

.

Astronomy

One of al-Battānī's best-known achievements in astronomy
Astronomy
Astronomy is a natural science that deals with the study of celestial objects and phenomena that originate outside the atmosphere of Earth...

 was the determination of the solar year as being 365 days, 5 hours, 46 minutes and 24 seconds.

He was able to correct some of Ptolemy
Ptolemy
Claudius Ptolemy , was a Roman citizen of Egypt who wrote in Greek. He was a mathematician, astronomer, geographer, astrologer, and poet of a single epigram in the Greek Anthology. He lived in Egypt under Roman rule, and is believed to have been born in the town of Ptolemais Hermiou in the...

's results and compiled new tables of the Sun
Sun
The Sun is the star at the center of the Solar System. It is almost perfectly spherical and consists of hot plasma interwoven with magnetic fields...

 and Moon
Moon
The Moon is Earth's only known natural satellite,There are a number of near-Earth asteroids including 3753 Cruithne that are co-orbital with Earth: their orbits bring them close to Earth for periods of time but then alter in the long term . These are quasi-satellites and not true moons. For more...

, long accepted as authoritative. 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.

Al-Battānī discovered that the direction of the Sun's eccentric
Orbital eccentricity
The orbital eccentricity of an astronomical body is the amount by which its orbit deviates from a perfect circle, where 0 is perfectly circular, and 1.0 is a parabola, and no longer a closed orbit...

, as recorded by Ptolemy, was changing. He also discovered the movement of the Sun's apogee and introduced, probably independently of the 5th century India
India
India , officially the Republic of India , is a country in South Asia. It is the seventh-largest country by geographical area, the second-most populous country with over 1.2 billion people, and the most populous democracy in the world...

n astronomer Aryabhata
Aryabhata
Aryabhata was the first in the line of great mathematician-astronomers from the classical age of Indian mathematics and Indian astronomy...

, the use of sine
Sine
In mathematics, the sine function is a function of an angle. In a right triangle, sine gives the ratio of the length of the side opposite to an angle to the length of the hypotenuse.Sine is usually listed first amongst the trigonometric functions....

s in calculation, and partially that of tangents. He also calculated the values for the precession
Precession
Precession is a change in the orientation of the rotation axis of a rotating body. It can be defined as a change in direction of the rotation axis in which the second Euler angle is constant...

 of the equinoxes (54.5" per year, or 1° in 66 years) and the obliquity of the ecliptic (23° 35'). He used a uniform rate for precession in his tables, choosing not to adopt the theory of trepidation
Trepidation
According to a medieval theory of astronomy, trepidation is oscillation in the precession of the equinoxes. The theory was popular from the 9th to the 16th centuries....

 attributed to his colleague Thabit ibn Qurra
Thabit ibn Qurra
' was a mathematician, physician, astronomer and translator of the Islamic Golden Age.Ibn Qurra made important discoveries in algebra, geometry and astronomy...

.

Al-Battānī's work is considered instrumental in the development of science and astronomy. Copernicus
Nicolaus Copernicus
Nicolaus Copernicus was a Renaissance astronomer and the first person to formulate a comprehensive heliocentric cosmology which displaced the Earth from the center of the universe....

 mentioned his indebtedness to al-Battānī and quoted him in the book that initiated the Copernican Revolution
Copernican Revolution
The Copernican Revolution refers to the paradigm shift away from the Ptolemaic model of the heavens, which postulated the Earth at the center of the galaxy, towards the heliocentric model with the Sun at the center of our Solar System...

, the De Revolutionibus Orbium Coelestium
De revolutionibus orbium coelestium
De revolutionibus orbium coelestium is the seminal work on the heliocentric theory of the Renaissance astronomer Nicolaus Copernicus...

. Al-Battānī is also frequently quoted by Tycho Brahe
Tycho Brahe
Tycho Brahe , born Tyge Ottesen Brahe, was a Danish nobleman known for his accurate and comprehensive astronomical and planetary observations...

, Riccioli, among others. Kepler and Galileo also showed interest in some of his observations.

Mathematics

In mathematics
Islamic mathematics
In the history of mathematics, mathematics in medieval Islam, often termed Islamic mathematics or Arabic mathematics, covers the body of mathematics preserved and developed under the Islamic civilization between circa 622 and 1600...

, al-Battānī produced a number of trigonometrical
Trigonometry
Trigonometry is a branch of mathematics that studies triangles and the relationships between their sides and the angles between these sides. Trigonometry defines the trigonometric functions, which describe those relationships and have applicability to cyclical phenomena, such as waves...

 relationships:



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


He gives other trigonometric formulae, such as:


Al-Battānī used al-Marwazi
Al-Marwazi
Ahmad ibn 'Abdallah Habash Hasib Marwazi was an astronomer, geographer, and mathematician from Merv in Khorasan.He flourished in Baghdad, and died a centenarian after 869...

's idea of tangents
Trigonometric function
In mathematics, the trigonometric functions are functions of an angle. They are used to relate the angles of a triangle to the lengths of the sides of a triangle...

 ("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
Gnomon
The gnomon is the part of a sundial that casts the shadow. Gnomon is an ancient Greek word meaning "indicator", "one who discerns," or "that which reveals."It has come to be used for a variety of purposes in mathematics and other fields....

), for each degree from 1° to 90°.

Works

Al-Battānī's major work is Kitāb az-Zīj, or the book of astronomical tables, also known as az-Zīj aṣ-Ṣābi’. It was largely based on Ptolemy's theory, and other Greco-Syriac sources, while showing little Indian or Persian influence. In his zij
Zij
Zīj is the generic name applied to Islamic astronomical books that tabulate parameters used for astronomical calculations of the positions of the Sun, Moon, stars, and planets. The name is derived from the Middle Persian term zih or zīg, meaning cord...

, he provided descriptions of a quadrant
Quadrant (instrument)
A quadrant is an instrument that is used to measure angles up to 90°. It was originally proposed by Ptolemy as a better kind of astrolabe. Several different variations of the instrument were later produced by medieval Muslim astronomers.-Types of quadrants:...

 instrument.

This book went through many translations to Latin and Spanish, including a Latin translation as De Motu Stellarum by Plato of Tivoli
Plato Tiburtinus
Plato Tiburtinus was a 12th century Italian mathematician, astronomer and translator who lived in Barcelona from 1116 to 1138. He is best known for translating Hebrew and Arabic documents into Latin, and was apparently the first to translate information on the astrolabe from Arabic.Plato of...

 in 1116, which was later reprinted with annotations by Regiomontanus
Regiomontanus
Johannes Müller von Königsberg , today best known by his Latin toponym Regiomontanus, was a German mathematician, astronomer, astrologer, translator and instrument maker....

. A reprint appeared at Bologna
Bologna
Bologna is the capital city of Emilia-Romagna, in the Po Valley of Northern Italy. The city lies between the Po River and the Apennine Mountains, more specifically, between the Reno River and the Savena River. Bologna is a lively and cosmopolitan Italian college city, with spectacular history,...

 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.

Honors

  • The crater Albategnius
    Albategnius (crater)
    Albategnius is an ancient lunar impact crater located in the central highlands. It is named after the Muslim astronomer and scientist Al-Battani. The level interior forms a "walled plain", surrounded by the high, terraced rim. The outer wall is somewhat hexagon-shaped, and has been heavily eroded...

     on the Moon
    Moon
    The Moon is Earth's only known natural satellite,There are a number of near-Earth asteroids including 3753 Cruithne that are co-orbital with Earth: their orbits bring them close to Earth for periods of time but then alter in the long term . These are quasi-satellites and not true moons. For more...

     is named after him.
  • In the fictional Star Trek universe, the Excelsior-class starship USS Al-Batani [sic] NCC-42995, mentioned on Star Trek: Voyager
    Star Trek: Voyager
    Star Trek: Voyager is a science fiction television series set in the Star Trek universe. Set in the 24th century from the year 2371 through 2378, the series follows the adventures of the Starfleet vessel USS Voyager, which becomes stranded in the Delta Quadrant 70,000 light-years from Earth while...

    as Kathryn Janeway
    Kathryn Janeway
    Kathryn Janeway, played by Kate Mulgrew, is a fictional character in the Star Trek franchise. As the captain of the Starfleet starship USS Voyager, she was the lead character on the television series Star Trek: Voyager, and later, a Starfleet admiral, as seen in the 2002 feature film Star Trek...

    's first deep space assignment, was named for him.
  • The Doctor Who
    Doctor Who
    Doctor Who is a British science fiction television programme produced by the BBC. The programme depicts the adventures of a time-travelling humanoid alien known as the Doctor who explores the universe in a sentient time machine called the TARDIS that flies through time and space, whose exterior...

     novel Night of the Humans
    Night of the Humans
    Night of the Humans is a book in the Doctor Who New Series Adventures line, released on 22 April 2010. It features the Eleventh Doctor and Amy Pond as his companion.-Plot:...

    , features a solar system called Battani 045.

External links

(PDF version)

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