A disservice to the history of Islamic Astronomy

In an article on their website about their history Astronomy magazine claims to be the greatest magazine about astronomy in the world. If this were the case, one would expect them to maintain a high level of journalism and fact checking in the articles that they present to their readers. Unfortunately in at least one case this is far from being the truth. Recently I was guided by a link on Facebook to one of their articles, How Islamic scholarship birthed modern astronomy by Shannon Stirone. As always, interested in anything on the history of astronomy, particularly with such a provocative title I thought I would take a look and when I did then wished I hadn’t.

Ms Stirone makes a grand claim right away in the first paragraph:

Civilizations around the world have incorporated astronomical observations into everything from their architecture to their storytelling and while the pinnacle of the science is most commonly thought to have been during the Renaissance, it actually began a thousand years earlier and 5,000 miles to the East.

Unfortunately, she then goes completely off the rails in the very next paragraph:

Around the 6th century AD, Europe entered what’s known as the Dark Ages. This period of time from around 500 AD until to the 13th century witnessed the suppression of intellectual thought and scholarship around the continent because it was seen as a conflict to the religious views of the church. During this time the written word became scarce, and research and observations went dormant.

To repeat something that I seem to be saying rather oft recently, historians do not use the term Dark Ages anymore preferring the more neutral term Early Middle Ages but of course when you are about to spout pure historical bullshit using the derogatory term Dark Ages is a good way to prepare your unsuspecting readers. There was no “suppression of intellectual thought and scholarship around the continent because it was seen as a conflict to the religious views of the church.” In fact as Steve McCluskey points out in his excellent Astronomies and Cultures in Early Medieval Europe what learning and culture was kept alive during very troubling economic and political times in Europe was kept alive in the Christian monasteries, who of course also maintained a thriving written culture.  We move on:

While Europe was in an intellectual coma, the Islamic empire which stretched from Moorish Spain, to Egypt and even China, was entering their “Golden Age”. Astronomy was of particular interest to Islamic scholars in Iran and Iraq and until this time around 800 AD, the only astronomical textbook was Ptolemy’s Almagest, written around 100 AD in Greece. This venerable text is still used as the main reference for ancient astronomy in academia to this day. Muslim scholars waited 700 years for this fundamental Greek text to be translated into Arabic, and once it was, they got to work understanding its contents. 

Ignoring the dreadful writing style we get told, “Muslim scholars waited 700 years for this fundamental Greek text to be translated into Arabic.” Now if we follow the traditional dating and say that Islam begins in 622 CE then apparently the first translation of the Syntaxis Mathematiké (Almagest is of course the Arabic name for Ptolemaeus’ masterpiece) into Arabic was in the fourteenth century according to Ms Stirone’s reckoning. If, however, we take to conventional beginning of Islamic science to be the early eighth century then the poor Islamic astronomers had to wait until the fifteenth century! Even worse they, apparently, even had to wait for somebody else to translate if for them or at least that is what Ms Stirone’s wording would seem to imply. Apart from this Ptolemaeus lived and worked in Alexandria in Egypt not in Greece and the Syntaxis Mathematiké was written in about 150 CE not 100.

Next we jump to Ibn Yunus (c.950–1009):

Astronomers like Ibn Yunus from Egypt found faults in Ptolemy’s calculations about the movements of the planets and their eccentricities. Ptolemy was trying to find an explanation for how these bodies orbited in the sky, including how the Earth moved within these parameters. Ptolemy calculated that the wobble of the Earth, or precession as we now know it, varied 1 degree every 100 years. 

Later, astronomer Ibn Yunus found that Ptolemy was quite wrong and that in fact it was 1 degree every 70 years.

In fact Ptolemaeus knew it as precession because, as our author later admits  in her article he wasn’t aware that it was caused by wobble of the earth’s axis. Despite a fifth dan black belt in googling, I couldn’t find a source for Ibn Yunus’ value of the precession either on the Internet or in any of my books, so I’ll be generous and assume that our author is this time correct. However, what we have here is a wonderful example of presentism. Because Ibn Yunus’ value is close to the correct value we pick it out and ignore all the other incorrect values proffered by other leading Islamic astronomers. At the time nobody knew whose value was correct. Even worse various Islamic astronomers believed that the rate of precession varied over time and introduced the false concept of trepidation, which was passed on into European astronomy in the Renaissance. Not everything proffered by Islamic astronomy was correct or helpful.

We then get told:

This discovery by Ibn Yunus and others like Ibn al-Shatir changed the landscape of astronomy forever. The heliocentric model eventually proposed by Copernicus in the 16th century was built on this body of work.


Copernicus did indeed use the mathematical models developed by al-Shatir and others but there was nothing in the Islamic astronomy that he utilised that suggested or led to heliocentrism, as the quote above would seem to suggest. Also, Copernicus was one of the Renaissance astronomers who had to deal with the Islamic inheritance of the false theory of trepidation. Now on to mathematics:

The math required for astronomy was also advanced in large part by Islamic scholars. They developed spherical trigonometry and algebra, two forms of math fundamental to precise calculations of the stars. 

The algebra that Islamic mathematicians developed didn’t play a role in astronomy; trigonometry, however, did. Spherical trigonometry was originally developed by Hipparchus of Nicaea (c.190–c.120 BCE) and used by Ptolemaeus in his Syntaxis Mathematiké. Indian astronomers produced a better version of Ptolemaeus’ trigonometry and this was taken over and to some extent improved by Islamic mathematicians, who then passed it on to Europe in the Renaissance. We move onto observatories and observational instruments:

In the 8th century under Caliph al-Mamun al-Rashid, the first observatory was built in Baghdad and subsequent observatories were built around Iraq and Iran. Since this was before the telescope had been developed, the astronomers of the time invented observational sextants. These tools, some as large as 40 meters, were critical to the study of the angle of the sun, movement of the stars, and the understanding of the orbiting planets.

Although the mural sextant was a new development made by Islamic observers, ancient Greek astronomers also used instruments to make similar observations and measurements. Also the telescope was invented not developed. We continue:

Around this same time in 964, after more and more observations took place, one of Iran’s most famous astronomers Abd al-Rahman al-Sufi published The Book of Fixed Stars, one of the most comprehensive texts on constellations in the sky.  Abd al-Rahman al-Sufi was also the first astronomer to observe the Andromeda galaxy and the Large Magellanic Cloud. These observations would have been made purely with the naked eye since the telescope hadn’t yet been created. Of course he didn’t know it was a galaxy at the time, he marked it down as a “cloud” in his notes. This work would later prove to be useful to famed Danish astronomer Tycho Brahe.

Remember we are talking about how Islamic scholarship birthed modern astronomy, so I have to ask in what sense is this true for al-Sufi’s Book of Fixed Stars? A very beautiful manuscript that was known in many version in the Middle Ages and Renaissance, it is a synthesis of the Ptolemaic star catalogue and the pre-Islamic Arabic astronomical tradition. As a catalogue of the constellations it adds nothing to Ptolemaeus except a lot of Arabic names for stars that poor monoglot English speakers have difficulty spelling and even more difficulty pronouncing, Betelgeuse anyone? His records of the Large Magellanic and Andromeda nebulae are of historical interest but it would be centuries before astronomers would eventually understand what they are and al-Sufi only got credit for their “discovery” with hindsight. Next up al-Tusi:

Later in the 13th century, scientist and philosopher Nasir al-Din al-Tusi created the famous Tusi Couple. […] The Tusi Couple would later become critical to Copernicus’ understanding of these motions during his work in the Renaissance.

In the ellipsis we get a rather confused explanation of the fact that the Tusi Couple enables the construction of linear motion using circles. Yes, Copernicus did use the Tusi Couple but Copernicus’ insistence on reproducing all celestial motion with circular motion was his greatest error not his greatest achievement. Next up, he never fails to be included, is Ibn al-Haytham:

One of Islam’s most famous astronomers and scientific thinkers, Ibn al-Haytham, is known as “the father of optics” because he was the first person to crack the code about how we perceive light. He figured out that light traveled in a straight line into our eyes but not out. For hundreds of years it was thought by people like Ptolemy that our eyes actually emitted light, like an interior flashlight. His work developed the camera obscura and eventually aided in the development of the telescope.

That light travels in straight lines was a well-known fact in ancient Greek optics. There were also not just extra-mission theories of optics in ancient Greece but also intromission ones. Ibn al-Haytham’s achievement was to show that it was possible to combine an intromission theory of vision with the geometrical optics of Euclid, which was based on an extra-mission theory. To do so he used the punctiform theory of light reflection of al-Kindi, who propagated an extra-mission theory. It’s all much more complicated than it is, as here, usually presented. Although al-Haytham used the camera obscura it had been known since antiquity. His work in optics played no role in the invention of the telescope.

Perhaps the most significant contribution Ibn al-Haytham gave to the world was a methodical way of conducting experiments repeatedly in order to test a theory, this became known as the scientific method, the foundation for science as we know it.

If I ever get a tattoo it will be a quite long list of names, including Ibn al-Haytham’s, followed by the clause “…did not invent the scientific method!” We move onto higher education:

Throughout this time, from the beginning of the Golden Age until the early Renaissance, many universities and madrasas, or schools were being constructed around the Islamic empire. In 859 AD the first university was built in Fez, Morocco. It was conceived of and started by Fatima al-Fihri, the daughter of a wealthy merchant. Scholars from all over the world including Christian and Jewish scientists traveled there to study astronomy, math and philosophy.

One of my personal peeves is the use of the word university as a general term for institutes of higher education. Universities are institutes of higher education created in the High Middle Ages in Europe with a specific format and educational content. Earlier Islamic institutes of higher education are not universities. This is not saying that universities are in anyway superior just different. I’m not an expert on the history of Al Quaraouiyine the mosque and madrassa founded by Fatima al-Fihri, she only actually provided the funds for its establishment, which she inherited from her father, but I very much doubt the claim that Christian and Jewish scientists travelled there to study astronomy, maths, and philosophy, as it was basically a Muslim religious institutions for teaching Islamic theology.

Many schools and mosques around this time were overseen and managed by Muslim women who themselves had been educated in subjects ranging from literature to algebra, a form of math also perfected by Islam. One of the most well known astronomical tools called an Astrolabe was created by the Greek thinker Hipparcus but was perfected by islamic scientists, particularly women. Mariam al-Astrulabi was a Syrian female astrolab maker from the 10th century. She’s best known for perfecting the art of making these instruments which calculated the altitude of celestial bodies in the sky. In her honor, astronomer Henry E. Holt named a main belt asteroid after her in 1990.

Anybody like to comment on the “many schools and mosques around this time were overseen and managed by Muslim women”? Paint me sceptical. I’m not just sceptical about, “One of the most well known astronomical tools called an Astrolabe was created by the Greek thinker Hipparcus but was perfected by islamic scientists, particularly women. Mariam al-Astrulabi was a Syrian female astrolab maker from the 10th century.” I will admit that my knowledge of Islamic astrolabe makers is far from perfect but as far as I know Mariam al-Astrulabi is the only known female Islamic astrolabe maker and she is not known for perfecting the art of making these instruments.

The light from stars contain a history themselves; it’s taken tens of thousands of years in some cases for their story to travel through space and reach our eyes and mirrors of our telescopes. A millenia later, around 200 stars bear the Arabic names of astronomers who made significant contributions to the field.

Although many, many stars have Arabic names they were named by astronomers not after them. If you really want to know the meaning of the Arabic star names I recommend Paul Kunitzsch and Tim Smart, A Dictionary of Modern Star Names: A Short Guide to 254 Star Names and Their Derivations, Sky & Telescope, Cambridge Massachusetts, 2006.

Studying the cosmos is something more ingrained in the international culture than meets the eye. If you’ve ever stared at the belt of Orion or Alcor and Mizar, the binary stars in the Big Dipper, then you’ve gotten a small glimpse into the legacy created by Muslim scientists around the world.

The only thing that is really correct in this article in the fact that Islamic astronomers and astrologers made major contributions to the history of astronomy, which deserves to be elucidated and honoured but this shambling mess of an article does not do the job.  Given the size of the magazine Astronomy’s readership it is sad that they published this shoddy piece of journalism instead of commissioning somebody, who knows what they are actually talking about to write an article actually worthy of the inheritance of Islamic astronomy.
































Filed under History of Astronomy

4 responses to “A disservice to the history of Islamic Astronomy

  1. Mike from Ottawa

    Bruce Banner got nothing on our Thony C!

  2. “During this time the written word became scarce…”

  3. Around the 6th century AD, Europe entered what’s known as the Dark Ages. This period of time from around 500 AD until to the 13th century witnessed the suppression of intellectual thought and scholarship around the continent because it was seen as a conflict to the religious views of the church.

    Christ on a crutch. It will never end, will it?

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