1.Introduction
Baghdad the fairy city of the Arabian Nights and capital of the famous
Harun-ar-Rashid, the greatest emperor of his time, had the distinction of being
the foremost center of art and culture during the mediaval times. Renowned
scholars and translators, artists and scientists flocked to this great
metropolis from all parts of the world and adorned the learned assemblies of
Harun and Mamun, who besides being celebrated scholars themselves, were the greatest
patrons of learning that world has ever known. The Darul Hukama (House of
Wisdom) founded by Mamun-ar-Rashid in Baghdad housed some of the most eminent
scholars of the world belonging to different castes and creeds. The spade work
done by the scholars of the House of Wisdom provided the foundation by which
the stately edifice of Islamic learning was built. The caliphate of Mamun,
undoubtedly constitutes the most glorious epoch in saracenic history and has
rightly been called the “Augustan age of Islam”. “The twenty years of his
reign” says Ameer Ali, “Have left enduring monuments of the intellectual
development of the Muslim in all directories of thought. Their Achievements
were not restricted to any particular branch of science or literature, but ranged
over the whole course of the domain of intellect; speculative philosophy and
“belles letters” were cultivated with as much avidity as the exact sciences”.
“We see for the first time” says Oelsner, “Perhaps in the history of the world,
a religious and despotic government allied to philosophy, preparing and
partaking in its triumphs.”
Astronomy, in the real sense, started among the Arabs during the early
period of the Abbasid Caliphate. It was influenced by the Sidhanta, a work in
Sanskrit brought from India to Bagdad and translated into Arabic by Ibn Ibrahim
al-Farazi and later on by Abu Musa Khwarizmi. Pahlavi tables (zij) compiled
during the Sansanid period and Greek astronomical works translated during this
period prepared the ground for Arabian astronomy. Plolemy’s Al-magest went into
several translations in Arabic-the best being the one by Hajjaj Ibn Mater
(827-28) and another by Humayub Ibn Ishaq, revised by Thabit bin Qurra (D/901).
1.Khwarizmi
Khwarizmi has written a valuable treaties on astronomy and has compiled his
own Tables (zij) which, after two centuries was revised by Spanish astronomer
Majriti (011007) and translated into Latin by Adelard of Bath. This formed the
basis of later astronomical pursuits both in the East and the West and replaced
all earlier tables of Greek and Indian astronomers. This table was also adopted
in China.
1.Mashall and Ahmed bin Muhammad al-Nahavandi
Mashall and Ahmed bin Muhammad al-Nahavandi were earliest Arab astronomers
who flourished during the reign of Mansur, the second Abbasid Caliph. Mashallah
was called the Phoenix of his age by Abul Faraz. He is distinguished for
writing several valuable treatises on ‘Astrolabe’ the armillary sphere and the
movements of heavenly bodies which have been acclaimed by later scientists.
Ahmed compiled from his observations an astronomical table known as Al-Mustamal
which registered an advance over earlier notions of the Greeks and Hindus.
1.Caliph Mamunur Rashid
It was during the reign of Mamun, that practical steps were taken for to
advancement of astronomy and several observatories equipped with the latest
instruments were set up at various places in his domain. One of them was the
observatory in Jundeshapur, in south-west Persia. Early in the 9th century A.D
the first regular observations (Rasd) with the best available and fairly
accurate instruments were made in this observatory. Mamun got a degree of
meridian measured in the plain of Sanjar and followed a method which was much
superior to that of Greeks. The astronomical observations made during the reign
of Mamun regarding the equinoxes, the eclipses, the apparitions of the comets
and other celestial phenomena, have earned an important place in the
astronomical annals of mediaeval times. “The size of the earth was calculated”
says Ameer Ali “From the measurement of a degree on the shores of the Red
Sea-this at a time when Christian Europe was asserting the flatness of earth”.
Attached to his Darul Hukama (House of Wisdom), Mamun erected at Baghdad mear
the Shamsiyah gate, an astronomical observatory under the directorship of Sind
Ibn All, a converted Jew and Yahya Ibn Abi Mansur (830 or 831 A.D). According
to C.A Nallino, “Here astronomers made systematic observation of celestial
movements and verified with remarkably precise results all the fundamental
elements of the Almagest: the obliquity of the ecliptic, the precession of the
equinoxes, the length of the solar year etc”. With the aid of these
observations the astronomical tables called the Tested Tables or Tables of Mamun
were prepared. According to Ibn al-Ibri, Mamun later established another
observatory on Mt. Qasiyum outside Damascus. Afterwards several other
observatories were erected at Wasit, Apamea etc. Musa Bin Shakir was a well
known engineer during the reign of Harun-ar-Rashid. His sons specialized in
astronomical researches and earned a great reputation as astronomers during the
reign of Mamun and his two successors. Their research regarding the movements
of solar and other astral bodies, was remarkable. They ascertained the size of
the earth, the obliquity of the ecliptic, the variations of the lunar talitudes
and the precession of the equinoxes! The work of the sons of Musa-Bin Shakir
was continued by Al-Naziri and Muhammad Bin Isa Abu Abdullah, who made notable
additions to it. The invention of the telescope bu Abul Hasan forms a landmark
in the advancement of astronomical observations and in improved form, was used
with remarkable success in the observatories of Muragha, Cairo and Seville. A
number of Mamun’s astronomers headed by Musa Khwarizmi and Musa Ibn Shakir
successfully engaged in one of the most oblicate geodetic operations, i.e, the
determination of the size and the circumference of the earth. The measurement
carried out in the plain of Sanjar and also at accurate result, exceeding the
real length of the degree at the place by about 2877 feet, says C.A. Nallino-
“This would make the diameter of the earth 6500 miles and the circumference
20400 miles”. Muhammad Bin Musa al Khwarizmi a versatile genius of Islamic
history translated the Shidhanta or Indian tables and wrote a commentary on it.
He has written a valuable treatise on astronomy and has compiled his own tables
(zij) which after two centuries were revised by the Spanish astronomer Majriti
and translated into Latin by Adelard of Bath in 1126 A.D. These formed the
basis of later astronomical works in the East and the West, replacing all
earlier tables by Greek and Indian astronomers. These tables were also used in
China.
1.Ibrahim Al-Farazi
Ibrahim Al-Farazi was the first Muslim to construct an astrolabe. He wrote
on the use of the armillary sphere and prepared tables in accordance with
Arabic years. One of the earliest Arabic treatises on this instrument was
written by Isa-al-Astulabi who resided in Baghdad at about 830 A.D.
1.Abul Abbas al-Farghani
Abul Abbas al-Farghani (Alfraganus), a resident of Farghana in Central
Asia, was an astronomer of repute, who in 861 A.D according to Ibn Abi Usabiyah
(Vol. 1, page 207), supervised for the Abbasid Caliph Al-Mutawakkil the
erection of a Nilometer at Fustat.
His well-known work Al-Mudkhil-ila-ilm-hayat-al-aflak (compendium of
astronomy) was translated into Latin in 1135 A.D., by John of Seville and
Gerard of Cremona. It was also rendered into Hebrew. “The introduction of
Astronomy into Christian Europe” says, J.W Drapaer, “has been attributed to the
translation of the works of Muhammad Fargani. In Europe, also, the Arabs were
the first to build observatories, the Giralda, or Tower of Seville was erected
under the superintendence of Geber, the mathematician”.
1.Buwayhid Sultans
The Buwayhid Sultans were also great patrons of learning and were
surrounded by a galaxy of talented scholars invited from the four corners of
the Islamic world. The Buwayhid Sultan Sharaf al-Dulah (982-989) founded a good
observatory in his place at Baghdad where such celebrated as Abdur Rahman
al-Sufi, Ahmad al-Saghani and Abul Wafa carried on their research. Abdur Rahman
al Sufi wrote al-kawakib al Sabitah (fixed stars) which is known as a
masterpiece of observational astronomy. Alkohli, another astronomer attached to
the same dynasty, studied the movements of the planets and his research
regarding the summer solstice and the autumnal equinox were of considerable
value. Abul Wafa, born in 939 A.D in Khorosan and established in Iraq was an
outstanding mathematician and astronomer, who introduced the use of the secant
as well as the tangent into astronomical observations. Another buwayhid ruler,
Rukh al- Daulah, (932-976 A.D) partonised Abu Jafr al Khazin, a well-known
astronomer of Khorasan, who ascertained “The obliquity of the ecliptic and
solved a problem of Archimedes which leads to a cubic equation”.
1.Ali Ibn Amajur and Abul Hasan Ali Ibn Amajur
By the close of the tenth century A.D, Baghdad was thronged with hundreds
of astronomers including Ali Ibn Amajur amd Abul Hasan Alon Ibne Amajur who are
known for their accurate calculation of the lunar movements.
1.Abu Abdullah Ibn Muhammad Ibn Jabir al Battani
Abu Abdullah Ibn Muhammad Ibn Jabir al Battani (Albategnius 877-918 A.D) a
Sabian from Haram was one of the most illustrious astronomers of the East who
is known as the Ptolemy of the Arabs. His tables translated into Latin formed
the basis for astronomical work in Europe for several centuries. He also wrote
a voluminous treatise on the subject and his astronomical tables were an
advance over those of Khwarizmi and the Indians. He carried on his studies and
observations in al-Raqqah. He was an outstanding original writer and a research
scholar of repute who made several emendations to Ptolemy and rectified the
calculations for the orbits of the moon and certain other planets. According to
Philip k Hitti, “He’s proved the possibility of annular eclipses of the sun and
determined with greater accuracy of obliquity of the ecliptic, the length of
the tropical year, end of the seasons and the mean orbit of the sun”.
Persian, which after the downfall of the Abbasid Caliphate formed the nerve
center of Islamic learning, produced some of the greatest intellectuals of
mediaeval times. Great advances were made in almost all branches of knowledge.
One of the most outstanding itekkectulas of Islam was Abu Rehan Beruni
(973-1048 A.D) who graced the literacy meetings of Mahmud Ghaznaui. “Few know
physics and metaphysics” says J. N Sircar, the celebrated Indian Historian,
“amongst those few the greatest in Asia was Al-Beruni, at once a philosopher
and a scientist and preeminent in both of those two seemingly incompatible
fields”. Al-Beruni was distinguished and original scholar of astronomy and
other sciences. His Al-Qanun al Masudi written for his patron Sultan Masud
Ghazni in 1030 A.D is an astronomical encyclopedia. A short catechism of
geometry, arithmetic, astronomy and astrology also written in 1030 A.D. and
entitled Ak-Tahfin Li awail sinaat al-I\rajum deals chiefly with the calenders
and eras of ancient peoples. The rotation of the earth on its axis and the
accurate determination of longitude and latitudes were also elaborately discussed
in this book. 10. Malik Shah Saljuqi and Nizamul Mulk Toosi
Malik Shah Saljuqi and his illustrious grand vazir Nizamul Mulk Toosi were
also great patrons of learning during those times. They established an
observatory at Rayy or Neshapur in 1074-1075 A.D. where under the guidance of
Omar Khayyam and Abdur Rahman al Hazini astronomical observations were made.
Their research led to a reformed calendar which preceded the Gregorian calendar
by 600 years. According to Sedillot, who is an authority on the subject, “it is
more exact”. Jalaluddin Malik Shah Seljuqim and is based on an accurate
determination of the length of the tropical year. The Gregorian calendar leads
to an error of one day in 3330 years whereas Khayyams apparently leads to an
error of one day in about 5000 years.
The destruction wrought by the Mongol hordes served a death blow to all
cultural and intellectual movements in the world of Islam. The cultural
treasures amassed during centuries of intellectual pursuits was reduced to
ashes. On the downfall of the Abbasid Caliphate there sprang up small Muslim
principalities who kept aloft the candle of learning and vied with each other
in the patronage of scholars and scientists. A year after the fall of Baghdad,
in 1259 A.D., Hulagu Khan started the construction of the Khaniz observatory in
Maragah (Turkistan). This was the best observatory of its time, working under
the directorship of the celebrated genius and astronomer of the era, Nasiruddin
Toosi, and equipped with the best available instruments including and armillary
sphere, the mural quadrant and solstitial armil. The remains of this
observatory are still extant and it was here that Toosi compiled his
astronomical tables known as al zij al il khani which earned much popularity
throughout Asia including China. Nasiruddin Toosu also wrote Tazkirah fi ‘ilm
al Hai’a, ab outstanding work on astronomy.
Samarqand, the capital of the famous conqueror Tamerlane became in those
days a great center of Islamic education. An astronomical table prepared in
1437 for prince of the family of Tamerlane and called Table of Ulugh Beg was
much appreciated in Europe and according to Carra De Vaux was published in
England in the 18th Century.
The Arab civilization of Spain rivaled that of the Abbasid in the East, and
during the middle of the 10th Century astronomical studies were especially
favoured by the rulers of Muslim Spain. The outstanding Spanish astronomers
were Majriti of Cordova, al Zarqali (1029-1087 A.D) of Toledo, Ibn Afuag of
Seville and Nur-ud-din Abu Ishaq-al-Bitruji.
In famous work Kitab al Hayat (book of astronomy) which was later
translated intro Latin by Gerard of Cremona, Jabir Ibn Afiah, the celebrated
astronomer of the twelfth century, sharply criticized Ptolemy. Against the
observations of Ptolemy he rightly observed that lower planets, Mercury and
Venus, have no visible parallaxes. His generalizations of the subject were
confirmed by later research.
1.Al-Zarqali
Al-Zaraqali ( Arzachel 1029-1087 A.D) was the foremost astronomical observer
of Muslim Spain. He was the celebrated instrument maker who constructed an
improved tupe of astrolabe ( a saJilza) on which he wrote a treatise. His
calculations of the length of the Mediterranean Sea as 42 degrees was
approximately accurate in comparison to Ptolemy’s estimate of 62” and
Al-Khwaruzmi’s estimate of 52”. He also has the distinction of being the first
astronomer to prove the motion of the solar apogee with reference to stars. His
works along with those of Al-Battani were studied and appreciated in the West
and Copernicus quotes him in his well known work De Revolutionibus Orbizrm
Coeletium.
12. Nur-ud Din Abu Ishaq al
Bitruji
Nur-ud Din Abu Ishaq al Bitruji (Alpetragius), was foremost among the last
astronomers of Spain, whose outstanding work Kitab-al-Hai’a translated into
Latin by Michael Scot in 1217 and into Hebrew in 1259 A.D. He is considered the
exponent of a new astronomy and his book marks the culmination of the
anti-Ptolemaic movement. According to Draper, increased accuracy was given to
the correction of the astronomical observations by Alhazen’s great discovery of
atmospheric refraction.”
The first observatory in Europe was built by Arabs in Seville. The famous
astronomical tower of Seville was constructed under the supervision of Jabir
Ibn Afiah in 1190 A.D. With the fall of the Muslim power in Spain it was turned
into a belfry by the Christians conquerors who did not know what else to do
with it.
“Finally, it was though Spanish Channels” says Philip K. Hitti “That the
Latin West found its orental inspiration in astronomy and astrology. The
leading Muslim astronomical works were translated in Spain into Latin, and the
Alfonsine tables complied under the aegis of Alfonso X in the 13th Century were
but a development of Arab astronomy. According to R Briffault, “Arab astronomy
did not forestall Copernicus or Newton, though without it there would have been
no Copernicus and Newton.”
Conclusion
The Muslim have thus made the
greates contributions to astronomical knowledge during mediaeval times.
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