Historical Data Surah 85 · Ayah 1
Contributions of early Muslim astronomers to the field of astronomy
Contributions of early Muslim astronomers to the field of astronomy
Contribution of early Muslim astronomers in the field of astronomy and the use of astrolabes for the study of the stars in the night sky
Oliver Hoare once said "The ability of Islamic civilization to perfect what it inherited, and to endow what it made with beauty, is nowhere better expressed than in the astrolabe". Over a thousand-year period in Muslim Civilisation, epoch-making discoveries and contributions, such as the first record of a star system outside our own galaxy were made. Also astronomical instruments including celestial globes, armillary spheres, sextants and especially astrolabes were developed laying the foundation for modern-day astronomy.
Astro is defined as “star” in Greek, “+labe” from the Greek word labio meaning “taker” - in this sense, perhaps even "thief" - but it is better known as “finder”. In English, astrolabe has a very cool name which can literally be interpreted as STAR-FINDER”, sounding like a spaceship or superhero name from a science-fiction movie!
Over a thousand-year period in Muslim Civilisation, epoch-making discoveries and contributions, such as the first record of a star system outside our own galaxy were made. Also astronomical instruments including celestial globes, armillary spheres, sextants and especially astrolabes were developed laying the foundation for modern-day astronomy. For example, according to Franz S Verlag, “Al-Farghani” wrote the first known substantial description of the astrolabe during the years 856-57 AD, the date of the star table, which was based on the Mumlahan Tables”. People from Muslim Civilisation continued to use and contribute extensively to this device that making astrolabes became an art.
Today the oldest functional astrolabes discovered are mostly from Muslim Civilisation and some of them sold in very high prices in auctions for their elegance and history. This article will try to explore the origins of astrolabes, its types, uses and much more.
The astrolabe, Professor David A. King defines, is a two-dimensional model of the universe that one can hold in one’s hands; its heavenly features include a star map and the ecliptic (both appearing in the rete), and its terrestrial features (engraved on various plates) serve specific latitudes or localities.
Some astrolabes were small, palm-size, and portable; others were huge. They were the astronomical analog computers of their time, solving problems relating to the position of celestial bodies, like the sun and stars, and time. In effect, they were the pocket watches of medieval astronomers. They could take altitude measurements of the sun; could tell the time during the day or night; or find the time of a celestial event such as sunrise, sunset, or culmination of a star.
The astrolabe is thought to have originated in Ancient Greece. Though no working examples have survived, Hipparchus, writing in around 150 BCE, is credited with discovering stereographic projection, the mathematical means of representing the 3D sky onto a 2D plate that is the basis of how the astrolabe works.
While the origin of the astrolabe may have been Greek, it is generally agreed that the design was then perfected in Muslim Civilisation – indeed the name Astrolabe comes from the Arabic (asturlab) which is a version of the Greek term astrolabos (star-holder/taker), but it is in the Golden Age of Muslim Civilisation that the astrolabe was highly developed and its uses widely multiplied. Introduced to Europe from Muslim Spain in the early 12th century, it was one of the major astronomical instruments until the modern times.
"The astrolabe has many applications, such as working out heights of inaccessible objects, time of day and its position on earth. This is all done by the use of ingenious tables and figures that are imprinted on both sides of an astrolabe." It has many uses that astronomers in Muslim Civilisation recorded. For example, 10th century famous astronomer Abdul-Rahman al-Sufi outlined over 1,000 uses of an astrolabe in his writings.
Using stereography, celestial spheres were enabled to be projected on to a 2D plane and form the important body of an astrolabe. These astrolabes were based on the ecliptic, and divided into 12 portions. Further, each portion was given a sign of the zodiac.
As there are many uses, there are many makers of Astrolabes as some of them mentioned in this story.
The making of astrolabes, a branch of applied science of great status, was practiced by many include one woman from Aleppo (Syria), Mariam (*note above) “Al-Astrolabiya” Al-Ijliya (Al-'Ijliyah bint al-'Ijli al-Asturlabi), who followed her father's profession and was employed at the court of Sayf al-Dawlah (333 H/944 CE-357/967), one of the powerful Hamdanid rulers in northern Syria who guarded the frontier with the Byzantine empire in the tenth century CE.
Another name should be specially mentioned here "This remarkable astronomical instrument was made by the Muslim astronomer known as Nastūlus, who was active in Baghdad between 890 and 930. Its rediscovery brings our knowledge of the activities in that flourishing scientific centre a substantial step further" as Prof David A. King continues:
Most known ones are called Universal Astrolabes. These were developed in Toledo in the 11th century, and it revolutionized star mapping. Two individuals, Ali ibn Khalaf al-Shajjar, an apothecary or herbalist, and Al-Zarqali, were important in this new development. The universal astrolabe was a major breakthrough because it could be used at any location. Ordinary astrolabes needed different latitude plates if they were moved, because they were designed for a certain place and were latitude dependent.
An important aspect of the universal astrolabe was that its stereographic projection used the vernal or autumnal equinox as the center of projection onto the plane of the solstitial colure.
There are, of course other types of astrolabe such as Nautical, Quadrant, Rojas Astrolabes, and Planispheric Astrolabe was one of the most popular one. Other one of the most interesting of them all was an astrolabe with geared calendar made by Muhammad b. Abi Bakr, Isfahan, 1221/2 as shown below. Muhammad ibn Abi Bakr al-Farisi (d.1278) was an Islamic astronomer born in Aden (Yemen). He is the author of al-Tuḥfa, which includes a treatise containing important information for the history of Islamic astronomy and its connection with the religion of Islam. This early Persian astrolabe with a geared calendar movement is the oldest geared machine in existence in a complete state. It illustrates an important stage in the development of the various complex astronomical machines from which the mechanical clock derives. Scholars from Muslim Civilisation learned of this design from a text by al-Bîrûnî, who explained how gearing might be used to show the revolutions of the sun and moon at their relative rates, and to demonstrate the changing phase of the moon. These phenomena were of fundamental importance in the lunar calendar used in Muslim Civilisation.
Astrolabes were the cutting edge of technology, used and developed by astronomers in Muslim Civilisation who were intrigued and fascinated by the heavens. It was through these hard working scholars that the astrolabe made it into Europe, where modern astronomy was born. Astrolabes, as an instrument for timekeeping, were eventually superseded by mechanical clocks and more advanced methods of calculation, but simplified astrolabes for stargazers are still made today.