Arzachel
Encyclopedia
, Al-Zarqali, Ibn Zarqala (1029–1087), Latinized as Arzachel, was an instrument maker and one of the leading theoretical and practical astronomers
of his time. Although his name is conventionally given as al-Zarqālī, it is probable that the correct form was al-Zarqālluh. He lived in Toledo
in Castile
, Al-Andalus
(now Spain
), moving to Córdoba
later in his life. His works inspired a generation of Islamic astronomers in Andalusia
.
The crater Arzachel
on the Moon
is named after him.
converts to Islam
in a village near the outskirts of Toledo
, then a famous capital of the Taifa of Toledo
, known for its co-existence between Muslims and Christians.
He was trained as a metalsmith and due to his skills he was nicknamed Al-Nekkach (in Andalusian Arabic "the engraver of metals"). According to the historians of Al-Andalus
he was a mechanic
and metal-craftsman very crafty with his hands.
He was particularly talented in Geometry
and Astronomy
. He is known to have taught and visited Córdoba
on various occasions his extensive experience and knowledge eventually made him the foremost foremost astronomer of his time
. Al-Zarqālī was not only just a Theoretical scientist but an inventor as well. His inventions and works put Toledo
at the intellectual center of Al-Andalus
.
In the year 1085 Toledo was sacked by Alfonso VI of Castile Al-Zarqālī like his colleagues such as al‐Waqqashi (1017–1095) of Toledo
had to flee for his life. It is unknown whether the aged Al-Zarqālī fled to Cordoba
or died in a Moorish refuge camp.
His works profoundly influenced the works of: Ibn Bajjah
(Avempace), Ibn Tufail
(Abubacer), Ibn Rushd (Averroës), Ibn al-Kammad
, Ibn al‐Haim al‐Ishbili
and Nur ad-Din al-Betrugi (Alpetragius).
In the 12th century, Gerard of Cremona
translated al-Zarqali’s works into Latin. Ragio Montanous wrote a book in the 15th century on the advantages of the Sahifah al-Zarqalia. In 1530, the German scholar Jacob Ziegler
wrote a commentary on al-Zarqali’s book. In his "De Revolutionibus Orbium Coelestium" in the year 1530, Nicolaus Copernicus
quotes the works of al-Zarqali and Al-Battani
.
in a section of the Libros del Saber de Astronomia entitled the "Libros de las laminas de los vii planetas".
He also invented a perfected kind of astrolabe
known as "the tablet of the al-Zarqālī" (al-ṣafīḥā al-zarqāliyya), which was famous in Europe under the name Saphaea.
There is a record of an al-Zarqālī who built a water clock
, capable of determining the hours of the day and night and indicating the days of the lunar months. According to a report found in al-Zuhrī
's Kitāb al-Juʿrāfīyya, his name is given as Abū al-Qāsim bin ʿAbd al-Raḥmān, also known as al-Zarqālī, which made some historians think that this is a different person.
and Al-Khwarizmi. Specifically, he corrected Ptolmey’s estimate of the length of the Mediterranean sea
from 62 degrees to the correct value of 42 degrees In his treatise on the solar year, which survives only in a Hebrew translation, he was the first to demonstrate the motion of the solar apogee
relative to the fixed background of the stars. He measured its rate of motion as 12.9 seconds per year, which is remarkably close to the modern calculation of 11.6 seconds. Al-Zarqālī's model for the motion of the Sun, in which the center of the Sun's deferent moved on a small, slowly-rotating circle to reproduce the observed motion of the solar apogee, was discussed in the thirteenth century by Bernard of Verdun
and in the fifteenth century by Regiomontanus
and Peurbach. In the sixteenth century Copernicus employed this model, modified to heliocentric form, in his De Revolutionibus Orbium Coelestium
.
, an adaptation of earlier astronomical data to the location of Toledo along with the addition of some new material. Al-Zarqālī was famous as well for his own Book of Tables. Many "books of tables" had been compiled, but his almanac
contained tables which allowed one to find the days on which the Coptic, Roman, lunar, and Persian months begin, other tables which give the position of planets at any given time, and still others facilitating the prediction of solar and lunar eclipses.
He also compiled an almanac that directly provided "the positions of the celestial bodies and need no further computation". The work provided the true daily positions of the sun for four Julian years
from 1088 to 1092, the true positions of the five planets every 5 or 10 days over a period of 8 years for Venus, 79 years for Mars, and so forth, as well as other related tables.
His Zij
and Almanac
were translated into Latin by Gerard of Cremona
in the 12th century, and contributed to the rebirth of a mathematically-based astronomy
in Christian Europe and were later incorporated into the Tables of Toledo
in the 12th century and the Alfonsine tables
in the 13th century.
In designing an instrument to deal with Ptolemy's complex model for the planet Mercury
, in which the center of the deferent moves on a secondary epicycle, al-Zarqālī noted that the path of the center of the primary epicycle is not a circle, as it is for the other planets. Instead it is approximately oval
and similar to the shape of a pignon
. Some writers have misinterpreted al-Zarqālī's description of an earth-centered oval path for the center of the planet's epicycle as an anticipation of Johannes Kepler
's sun-centered elliptical paths
for the planets. Although this may be the first suggestion that a conic section
could play a role in astronomy, al-Zarqālī did not apply the ellipse to astronomical theory and neither he nor his Iberian or Maghrebi contemporaries used an elliptical deferent in their astronomical calculations.
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...
of his time. Although his name is conventionally given as al-Zarqālī, it is probable that the correct form was al-Zarqālluh. He lived in Toledo
Toledo, Spain
Toledo's Alcázar became renowned in the 19th and 20th centuries as a military academy. At the outbreak of the Spanish Civil War in 1936 its garrison was famously besieged by Republican forces.-Economy:...
in Castile
Kingdom of Castile
Kingdom of Castile was one of the medieval kingdoms of the Iberian Peninsula. It emerged as a political autonomous entity in the 9th century. It was called County of Castile and was held in vassalage from the Kingdom of León. Its name comes from the host of castles constructed in the region...
, Al-Andalus
Al-Andalus
Al-Andalus was the Arabic name given to a nation and territorial region also commonly referred to as Moorish Iberia. The name describes parts of the Iberian Peninsula and Septimania governed by Muslims , at various times in the period between 711 and 1492, although the territorial boundaries...
(now Spain
Spain
Spain , officially the Kingdom of Spain languages]] under the European Charter for Regional or Minority Languages. In each of these, Spain's official name is as follows:;;;;;;), is a country and member state of the European Union located in southwestern Europe on the Iberian Peninsula...
), moving to Córdoba
Córdoba, Spain
-History:The first trace of human presence in the area are remains of a Neanderthal Man, dating to c. 32,000 BC. In the 8th century BC, during the ancient Tartessos period, a pre-urban settlement existed. The population gradually learned copper and silver metallurgy...
later in his life. His works inspired a generation of Islamic astronomers in Andalusia
Andalusia
Andalusia is the most populous and the second largest in area of the autonomous communities of Spain. The Andalusian autonomous community is officially recognised as a nationality of Spain. The territory is divided into eight provinces: Huelva, Seville, Cádiz, Córdoba, Málaga, Jaén, Granada and...
.
The crater Arzachel
Arzachel (crater)
Arzachel is a relatively young lunar impact crater located in the highlands in the south-central part of the visible Moon, close to the zero meridian . It lies to the south of the crater Alphonsus, and together with Ptolemaeus further north the three form a prominent line of craters to the east of...
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.
Early life
Al-Zarqālī was born to a family of VisigothVisigoth
The Visigoths were one of two main branches of the Goths, the Ostrogoths being the other. These tribes were among the Germans who spread through the late Roman Empire during the Migration Period...
converts to Islam
Islam
Islam . The most common are and . : Arabic pronunciation varies regionally. The first vowel ranges from ~~. The second vowel ranges from ~~~...
in a village near the outskirts of Toledo
Toledo, Spain
Toledo's Alcázar became renowned in the 19th and 20th centuries as a military academy. At the outbreak of the Spanish Civil War in 1936 its garrison was famously besieged by Republican forces.-Economy:...
, then a famous capital of the Taifa of Toledo
Taifa of Toledo
The taifa of Toledo was a Muslim medieval kingdom located in what is now central Spain. It existed from the fracturing of the long-eminent Muslim Caliphate of Córdoba in 1035 until the Christian conquest in 1085.-History:...
, known for its co-existence between Muslims and Christians.
Al-Andalus
Al-Andalus was the Arabic name given to a nation and territorial region also commonly referred to as Moorish Iberia. The name describes parts of the Iberian Peninsula and Septimania governed by Muslims , at various times in the period between 711 and 1492, although the territorial boundaries...
he was a mechanic
Mechanic
A mechanic is a craftsman or technician who uses tools to build or repair machinery.Many mechanics are specialized in a particular field such as auto mechanics, bicycle mechanics, motorcycle mechanics, boiler mechanics, general mechanics, industrial maintenance mechanics , air conditioning and...
and metal-craftsman very crafty with his hands.
He was particularly talented in Geometry
Geometry
Geometry arose as the field of knowledge dealing with spatial relationships. Geometry was one of the two fields of pre-modern mathematics, the other being the study of numbers ....
and Astronomy
Astronomy
Astronomy is a natural science that deals with the study of celestial objects and phenomena that originate outside the atmosphere of Earth...
. He is known to have taught and visited Córdoba
Córdoba, Spain
-History:The first trace of human presence in the area are remains of a Neanderthal Man, dating to c. 32,000 BC. In the 8th century BC, during the ancient Tartessos period, a pre-urban settlement existed. The population gradually learned copper and silver metallurgy...
on various occasions his extensive experience and knowledge eventually made him the foremost foremost astronomer of his time
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...
. Al-Zarqālī was not only just a Theoretical scientist but an inventor as well. His inventions and works put Toledo
Toledo, Spain
Toledo's Alcázar became renowned in the 19th and 20th centuries as a military academy. At the outbreak of the Spanish Civil War in 1936 its garrison was famously besieged by Republican forces.-Economy:...
at the intellectual center of Al-Andalus
Al-Andalus
Al-Andalus was the Arabic name given to a nation and territorial region also commonly referred to as Moorish Iberia. The name describes parts of the Iberian Peninsula and Septimania governed by Muslims , at various times in the period between 711 and 1492, although the territorial boundaries...
.
In the year 1085 Toledo was sacked by Alfonso VI of Castile Al-Zarqālī like his colleagues such as al‐Waqqashi (1017–1095) of Toledo
Toledo, Spain
Toledo's Alcázar became renowned in the 19th and 20th centuries as a military academy. At the outbreak of the Spanish Civil War in 1936 its garrison was famously besieged by Republican forces.-Economy:...
had to flee for his life. It is unknown whether the aged Al-Zarqālī fled to Cordoba
Córdoba, Spain
-History:The first trace of human presence in the area are remains of a Neanderthal Man, dating to c. 32,000 BC. In the 8th century BC, during the ancient Tartessos period, a pre-urban settlement existed. The population gradually learned copper and silver metallurgy...
or died in a Moorish refuge camp.
His works profoundly influenced the works of: Ibn Bajjah
Ibn Bajjah
Abū-Bakr Muhammad ibn Yahya ibn al-Sāyigh , known as Ibn Bājjah , was an Andalusian polymath: an astronomer, logician, musician, philosopher, physician, physicist, psychologist, botanist, poet and scientist. He was known in the West by his Latinized name, Avempace...
(Avempace), Ibn Tufail
Ibn Tufail
Ibn Tufail was an Andalusian Muslim polymath: an Arabic writer, novelist, Islamic philosopher, Islamic theologian, physician, vizier,...
(Abubacer), Ibn Rushd (Averroës), Ibn al-Kammad
Ibn al-Kammad
Abu Jafar Ahmad ibn Yusuf ibn al‐Kammad was a Muslim astronomer born in Seville, Al-Andalus. He is known to have been educated in Cordoba by the students of Al-Zarqali...
, Ibn al‐Haim al‐Ishbili
Ibn al‐Haim al‐Ishbili
Abu Muhammad Abd al-Haqq al‐Ghafiqi al‐Ishbili was a Muslim astronomer, mathematician from Seville in Al-Andalus. He began his studies as a mathematician and studied the works of Al-Jayyani and Jabir ibn Aflah...
and Nur ad-Din al-Betrugi (Alpetragius).
In the 12th century, Gerard of Cremona
Gerard of Cremona
Gerard of Cremona was an Italian translator of Arabic scientific works found in the abandoned Arab libraries of Toledo, Spain....
translated al-Zarqali’s works into Latin. Ragio Montanous wrote a book in the 15th century on the advantages of the Sahifah al-Zarqalia. In 1530, the German scholar Jacob Ziegler
Jacob Ziegler
The humanist and theologian Jacob Ziegler of Landau, was an itinerant scholar of geography and cartographer, who lived a wandering life in Europe...
wrote a commentary on al-Zarqali’s book. In his "De Revolutionibus Orbium Coelestium" in the year 1530, Nicolaus 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....
quotes the works of al-Zarqali and Al-Battani
Al-Battani
Abū ʿAbd Allāh Muḥammad ibn Jābir ibn Sinān al-Raqqī al-Ḥarrānī al-Ṣābiʾ al-Battānī was a Muslim astronomer, astrologer, and mathematician...
.
Instruments
Al-Zarqālī wrote two works on the construction of an instrument (an equatorium) for computing the position of the planets using diagrams of the Ptolemaic model. These works were translated into Spanish in the 13th century by order of King Alfonso XAlfonso X of Castile
Alfonso X was a Castilian monarch who ruled as the King of Castile, León and Galicia from 1252 until his death...
in a section of the Libros del Saber de Astronomia entitled the "Libros de las laminas de los vii planetas".
He also invented a perfected kind of astrolabe
Astrolabe
An astrolabe is an elaborate inclinometer, historically used by astronomers, navigators, and astrologers. Its many uses include locating and predicting the positions of the Sun, Moon, planets, and stars, determining local time given local latitude and longitude, surveying, triangulation, and to...
known as "the tablet of the al-Zarqālī" (al-ṣafīḥā al-zarqāliyya), which was famous in Europe under the name Saphaea.
There is a record of an al-Zarqālī who built a water clock
Water clock
A water clock or clepsydra is any timepiece in which time is measured by the regulated flow of liquid into or out from a vessel where the amount is then measured.Water clocks, along with sundials, are likely to be the oldest time-measuring instruments, with the only exceptions...
, capable of determining the hours of the day and night and indicating the days of the lunar months. According to a report found in al-Zuhrī
Al-Zuhri
For the hadith scholar Al-Zuhri see Ibn Shihab al-Zuhri.Mohammed Ibn Abu Bakr al-Zuhri of Granada was a geographer. He was the writer of a notable work, Kitab al-Jaghrafiyya . Al-Zuhri was able to use the writings of the geographers of the reign of Caliph Al-Ma'mun of Baghdad For the hadith...
's Kitāb al-Juʿrāfīyya, his name is given as Abū al-Qāsim bin ʿAbd al-Raḥmān, also known as al-Zarqālī, which made some historians think that this is a different person.
Theory
Al-Zarqali corrected geographical data from PtolemyPtolemy
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...
and Al-Khwarizmi. Specifically, he corrected Ptolmey’s estimate of the length of the Mediterranean sea
Mediterranean Sea
The Mediterranean Sea is a sea connected to the Atlantic Ocean surrounded by the Mediterranean region and almost completely enclosed by land: on the north by Anatolia and Europe, on the south by North Africa, and on the east by the Levant...
from 62 degrees to the correct value of 42 degrees In his treatise on the solar year, which survives only in a Hebrew translation, he was the first to demonstrate the motion of the solar apogee
Apsis
An apsis , plural apsides , is the point of greatest or least distance of a body from one of the foci of its elliptical orbit. In modern celestial mechanics this focus is also the center of attraction, which is usually the center of mass of the system...
relative to the fixed background of the stars. He measured its rate of motion as 12.9 seconds per year, which is remarkably close to the modern calculation of 11.6 seconds. Al-Zarqālī's model for the motion of the Sun, in which the center of the Sun's deferent moved on a small, slowly-rotating circle to reproduce the observed motion of the solar apogee, was discussed in the thirteenth century by Bernard of Verdun
Bernard of Verdun
Little is known of the life of Bernard of Verdun, except that he was a Franciscan friar who may have been born in Verdun and lived in the second half of the thirteenth century...
and in the fifteenth century 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....
and Peurbach. In the sixteenth century Copernicus employed this model, modified to heliocentric form, in his 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...
.
Tables of Toledo
Al-Zarqālī also contributed to the famous Tables of ToledoTables of Toledo
The Toledan Tables, or Tables of Toledo, were astronomical tables which were used to predict the movements of the Sun, Moon and planets relative to the fixed stars...
, an adaptation of earlier astronomical data to the location of Toledo along with the addition of some new material. Al-Zarqālī was famous as well for his own Book of Tables. Many "books of tables" had been compiled, but his almanac
Almanac
An almanac is an annual publication that includes information such as weather forecasts, farmers' planting dates, and tide tables, containing tabular information in a particular field or fields often arranged according to the calendar etc...
contained tables which allowed one to find the days on which the Coptic, Roman, lunar, and Persian months begin, other tables which give the position of planets at any given time, and still others facilitating the prediction of solar and lunar eclipses.
He also compiled an almanac that directly provided "the positions of the celestial bodies and need no further computation". The work provided the true daily positions of the sun for four Julian years
Julian year (astronomy)
In astronomy, a Julian year is a unit of measurement of time defined as exactly 365.25 days of 86 400 SI seconds each, totaling 31 557 600 seconds. The Julian year is the average length of the year in the Julian calendar used in Western societies in previous centuries, and for which the unit is...
from 1088 to 1092, the true positions of the five planets every 5 or 10 days over a period of 8 years for Venus, 79 years for Mars, and so forth, as well as other related tables.
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...
and Almanac
Almanac
An almanac is an annual publication that includes information such as weather forecasts, farmers' planting dates, and tide tables, containing tabular information in a particular field or fields often arranged according to the calendar etc...
were translated into Latin by Gerard of Cremona
Gerard of Cremona
Gerard of Cremona was an Italian translator of Arabic scientific works found in the abandoned Arab libraries of Toledo, Spain....
in the 12th century, and contributed to the rebirth of a mathematically-based astronomy
Astronomy
Astronomy is a natural science that deals with the study of celestial objects and phenomena that originate outside the atmosphere of Earth...
in Christian Europe and were later incorporated into the Tables of Toledo
Tables of Toledo
The Toledan Tables, or Tables of Toledo, were astronomical tables which were used to predict the movements of the Sun, Moon and planets relative to the fixed stars...
in the 12th century and the Alfonsine tables
Alfonsine tables
The Alfonsine tables provided data for computing the position of the Sun, Moon and planets relative to the fixed stars....
in the 13th century.
In designing an instrument to deal with Ptolemy's complex model for the planet Mercury
Mercury (planet)
Mercury is the innermost and smallest planet in the Solar System, orbiting the Sun once every 87.969 Earth days. The orbit of Mercury has the highest eccentricity of all the Solar System planets, and it has the smallest axial tilt. It completes three rotations about its axis for every two orbits...
, in which the center of the deferent moves on a secondary epicycle, al-Zarqālī noted that the path of the center of the primary epicycle is not a circle, as it is for the other planets. Instead it is approximately oval
Oval
An oval is any curve resembling an egg or an ellipse, such as a Cassini oval. The term does not have a precise mathematical definition except in one area oval , but it may also refer to:* A sporting arena of oval shape** a cricket field...
and similar to the shape of a pignon
Pine nut
Pine nuts are the edible seeds of pines . About 20 species of pine produce seeds large enough to be worth harvesting; in other pines the seeds are also edible, but are too small to be of great value as a human food....
. Some writers have misinterpreted al-Zarqālī's description of an earth-centered oval path for the center of the planet's epicycle as an anticipation of Johannes Kepler
Johannes Kepler
Johannes Kepler was a German mathematician, astronomer and astrologer. A key figure in the 17th century scientific revolution, he is best known for his eponymous laws of planetary motion, codified by later astronomers, based on his works Astronomia nova, Harmonices Mundi, and Epitome of Copernican...
's sun-centered elliptical paths
Kepler's laws of planetary motion
In astronomy, Kepler's laws give a description of the motion of planets around the Sun.Kepler's laws are:#The orbit of every planet is an ellipse with the Sun at one of the two foci....
for the planets. Although this may be the first suggestion that a conic section
Conic section
In mathematics, a conic section is a curve obtained by intersecting a cone with a plane. In analytic geometry, a conic may be defined as a plane algebraic curve of degree 2...
could play a role in astronomy, al-Zarqālī did not apply the ellipse to astronomical theory and neither he nor his Iberian or Maghrebi contemporaries used an elliptical deferent in their astronomical calculations.
Works
Major Works and publications :- 1-"Al Amal bi Assahifa Az-Zijia";
- 2-"Attadbir";
- 3-"Al Madkhal fi Ilm Annoujoum";
- 4-"Rissalat fi Tarikat Istikhdam as-Safiha al-Moushtarakah li Jamiâ al-ouroud";
- 5-"Almanac Arzarchel";
See also
- Islamic astronomyIslamic astronomyIslamic 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...
- Islamic scholars
- List of Arab scientists and scholars
- Al-MuradiAl-MuradiAlī Ibn Khalaf al-Murādī, Al-Andalus, was an engineer and author of the unique technological manuscript entitled Kitāb al-asrār fī natā'ij al-afkār . It was copied and used at the court of Alfonso VI of León and Castile in Christian Spain in the 11th century...
Further reading
- E. S. Kennedy. A Survey of Islamic Astronomical Tables, (Transactions of the American Philosophical Society, New Series, 46, 2.) Philadelphia, 1956.