The Observatory of Maragha

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In the chaotic aftermath of Mongol expansion in the mid-13th century which had left the Abbasid capital of Baghdad in ruin, a new centre of learning soon came to the forefront. Ironically it was the very destroyer of Baghdad, Halaku Khan under whose auspices the Maragha Observatory was established in the Ilkhanate in today's North Western Iran.

The story goes that the astronomer, philosopher, theologian and mystic Nasiruddin Tusi was able to make a lasting impression on Halaku via his "divination" prowess and his expertise in astronomical computations. In the pre-modern world it was common to attribute worldly happenings to the positions of celestial objects on the sky.

Halaku, in pursuit of better political fortunes, saw fit to fund an establishment that could meticulously keep track of the stars and planets. Thus, under the supervision of Tusi, the Maragha Observatory was founded sometime in the 1250s. It served as a multifaceted institute with a wide array of functions. Most central of these was observing and recording the motions of heavenly objects as they trailed across the night sky.

A specific project undertaken at the observatory was the tracking of planetary motions. The distinction between planets and stars prior to the invention of the telescope was made on the basis of their respective motions. Planets move around, while stars do not. The word planet itself is derived from Greek planetes, which means wanderer. The planets were thought to go around the Earth, in perfectly circular orbits.

This so-called Geocentric model was the construction of famous Greek mathematician, astronomer Ptolemy. The model, though invaluable in helping to predict the positions of the stars and planets, had over time accumulated substantial errors. A certain motion of the Earth known as precession slightly offsets the positions of objects on the night sky.

Due to this, Tusi felt it was pertinent to make extensive and careful measurements of the stars and planets so that the Ptolemaic model could be salvaged for his particular time. His extensive observations were compiled and recorded in a text which came to be known as the Ilkhani Tables and became the basis of the work done by subsequent astronomers at Maragha.

The Observatory itself is thought by historians to have hosted a wide variety of intellectual activities in its vast and multi-floored complex. Students would be trained to operate instruments and record their findings. Compilations of the positions of celestial objects, known as zijs, would be kept in a library housing a plethora of manuscripts. Perhaps the largest observatory library of its time, it also served as a breeding ground for international collaborations. Scholars from other areas of the Mongol realms would travel to Maragha.

Records indicate the presence of astronomers from as far as China in a time which is stereotypically thought of as insular. Careful continuous observations of the planets were made over the course of a few decades. This of course was incumbent, given the longer times it takes the outer planets to revolve around the Sun. Saturn for instance takes 21 years to complete a full revolution, and the astronomers at Maragha observed its full course patiently.

This may sound trivial given how accustomed we are to receiving daily alerts about planetary whereabouts. However such an undertaking by the Maragha astronomers was nothing short of spectacular. With their carefully crafted instruments, including quadrants, celestial spheres and astrolabes, they were able to measure the positions of these planets incredibly accurately. Up to a few minutes of arc. For reference, the Moon and the Sun span an angle of 30 minutes of arc on the sky.

Tusi, the head astronomer, in addition to his observational pursuits, had also made strides in theoretical astronomy that made intellectual waves in the following centuries. For instance, he devised a theoretical construct, now known as Tusi Couple, to construct better models for planetary orbits. This device very simply consists of a small circle, contained within a larger circle. The smaller circle rotates inside of its larger counterpart. Curiously, the Tusi Couple shows up in the work of esteemed Prussian astronomer Nicolaus Copernicus.

In his book, On the Revolutions of the Heavenly Spheres, Copernicus introduces his Heliocentric model for the Universe which upended more than a millennia of Geocentric hegemony. In this work Copernicus has drawn a full-scale model of the Tusi Couple, labeled in a fashion eerily similar to the way Tusi himself had drawn it centuries prior in his memoir on astronomy titled Tadhkira.

How this transfer came across is a mystery but it is thought that the transmission route of this knowledge to Renaissance Europe must have gone through Maragha. This connection has led some scholars to view Copernicus as a follower of the Maragha school of astronomy. In the East the Maragha Observatory despite its fairly short lifetime (till the early 1300s) had a lasting effect for centuries to come.

It served as a model to emulate as demonstrated by the Istanbul Observatory established by Ottoman Sultan Murad III and the Samarqand observatory constructed by Ulugh Beg, grandson of the infamous Tamerlane. Ulugh Beg being a notable astronomer himself had visited Maragha in his youth.

In today's fast paced world it is all too easy to be dismissive of pre-modern attempts at learning. The Maragha Observatory is but one example of such a feat, where the brilliance of medieval astronomers is on display and still a source of fascination for modern day astronomers and historians.