Islamic Astronomers

Compiled By: Syed Ali Shahbaz
On July 4, 1054 AD, Islamic astronomers in Fatemid Egypt and the Iranian Buwayhid dominions of Iraq-Iran, as well as the Chinese, recorded the seeing of a supernova, a violently exploding star that was visible in daylight for 23 days and at night for almost 2 years. It is believed the Crab Nebula in the constellation Taurus is the remnant of this supernova. Rock paintings in North America suggest that Amerindians in Arizona and New Mexico also saw it. There are no European records of the event, since Christianity had plunged Europe into centuries of darkness. Some 48 years earlier in 1006, Islamic astronomers had recorded a supernova and given descriptions of how light varied and was visible for almost a year. This was history's brightest "new star" ever recorded, at first seen to be brighter than the planet Venus. It occurred in our Milky Way galaxy, appearing in the southern constellation Lupus, near the star Beta Lupi.
On July 4, 1483 AD, Tabulae Alphonsinae or the “Alphonsine Tables” were published by German printer Erhard Ratdolt in Venice. Among the earliest mathematical tables to be printed, these were a Latin translation made between 1262 to 1272 at the behest of King Alfonso X of Castile and Leon, of the Arabic Tables of the Muslim mathematician and astronomer, Abu Ishaq Ibrahim ibn Ishaq az-Zarqali (Arzachel to medieval Europe), who lived in Toledo, al-Andalus (Islamic Spain). Born in 1029 to a family of Christian Visigoths who converted to Islam, his works inspired a generation of Muslim astronomers in Islamic Spain including Ibn Bajjah (Avempace), Ibn Tufail (Abubacer), Ibn Rushd (Averroes), Ibn al-Kammad, Ibn al‐Ha’im al‐Ishbili and Nour od-Din al-Betruqi (Alpetragius).
Zarqali invented several astronomical instruments including an equatorium for computing the position of the planets. He corrected geographical data from the Greek astronomer Ptolemy and the Iranian astronomer al-Khwarezmi, specifically Ptolemy’s estimate of the length of the Mediterranean Sea from 62 degrees to the correct value of 42 degrees. He also invented a perfected kind of astrolabe known as “as-Safiha az-Zarqaliyya”, which was famous in Europe under the name Saphaea.
At a time when Christian Europe was immersed in the dark ages, he built a water clock, capable of determining the hours of the day and night and indicating the days of the lunar months at a time. Nicolaus Copernicus, who greatly benefitted from the works of Islamic scientists, has extensively quoted Zarqali and Al-Battani. In 1085 Toledo was occupied by Alfonso VI of Castile and his Christian mercenaries, prompting Zarqali and his colleagues, such as al‐Waqqashi (1017–1095) to flee. It is not known whether the aged Zarqali moved to Cordoba, which he often used to visit, or died in a refugee camp. The crater Arzachel on the Moon is named after him.
On June 11, 1292 AD, English philosopher and Franciscan friar, Roger Bacon, died. His access to the Latin translations of the Arabic works of Islamic scholars enlightened his mind, and he was greatly influenced in the field of optics by the monumental “Kitab al-Manazer” of Abul-Hassan Ibn al-Haytham (Alhazen).
The impact of al-Kindi (Alkindus) is also evident in his writings. Moreover, Bacon's investigations of the properties of the magnifying glass show the clear influence of Ibn Sahl's research in dioptrics. His works also indicate his familiarity with the books "Kitab ad‐Dalalaat ala'l‐Ittesalaat wa‐Qiranaat al‐Kawakeb" (Book of Indications of the Planetary Conjunctions), written by the Iranian Islamic astronomer, Abu-Ma'shar Ja'far ibn Mohammad al-Balkhi.
On June 11, 1855 AD, the Sun’s light rays were classified based on scientific approaches and the colors of its spectrum were identified by two German scientists, Gustav Kirchhoff and Robert Bunsen. The radiation of light beams during rainfall, and formation of rainbows, is one of the beautiful phenomena that have attracted the attention of mankind since eternity.
The Theory of Aristotle is the oldest theory which other scientists became familiar with. Later the Islamic scientists, Abu Ali ibn Sina (Avicenna), Abul-Hassan Ibn al-Haytham (Alhazen), and Qotb od-Din Shirazi developed this field. Finally, Kirchhoff and Bunsen proved it via an experimental method.
On June 22, 1633 AD, Italian astronomer, mathematician, and physicist, Galileo Galilei, was forced to renounce his scientific remarks and beliefs before the Church officials. Influenced by the Latin translations of the Arabic works of Islamic scientists, such as Iran’s Abu Rayhan Berouni, he wrote a book in the year 1632 in rejection of Ptolemy’s beliefs on solar system, supporting the fact that the Earth orbits round the Sun. A year later, Pope summoned him to Rome and termed his writings as blasphemous, and gave him the option of denying what he said or death.
On January 8, 1642 AD, the Italian scientist, astronomer, and physicist, Galileo Galilei, died at the age of 78. Born in the city of Pisa, he studied literature until the age of 19 and thereafter mastered physics and mathematics. With the usage of lens, invented by the famous Muslim astronomer, Ibn al-Haytham, he developed a telescope for observing stars. With this instrument, and with the aid of the writings of Islamic scientists, he wrote that the surface of moon has plains and altitudes and each galaxy is made of small and large stars.
He also recorded as his own discoveries of Islamic scientist that the sun is at the centre of the Solar System and other planets, including Earth, revolve round it. These discoveries were already made several centuries earlier in the Islamic world by the renowned Iranian astronomer, Abu-Rayhan Birouni, who had proved the circular movement of earth around the sun. Following the publication of Galileo’s theory about the movement of earth and other planets of the solar system round the sun, the Roman Church charged him with blasphemy, forcing him to renounce his views or risk execution.
On January 13, 1450 AD, the Portuguese sailor and explorer, Bartholomew Diaz, was born. In 1488, after sailing the Atlantic Ocean toward the south, with the help of Muslim navigators, he became the first European to land on the Cape of Good Hope, in the most southern region of African Continent. Ten years after Diaz, his compatriot, Vasco da Gama, again with the help of Muslim navigators, became the first European to discover the sea route to India by rounding the southern peninsular tip of Africa. The discovery of this sea route was important for the West because the Ottoman Turks, after conquering Constantinople in the year 1453 and renaming it Istanbul had blocked Europe’s path to Asia. Diaz died in the year 1500.