The Istanbul and Uraniborg Observatories: A Comparative Study

Written by Kat Jivkova. Both the Istanbul and Uraniborg observatories were pioneers in the fields of astronomy and alchemy. Despite the cultural schism between them, comparative study can elucidate significant advances in astronomic practice in the sixteenth century.

Cross-cultural scientific interaction between the Eastern Mediterranean and Europe was exacerbated in the early modern period, fuelled by rivalling scientific traditions. While Islamic astronomy continued to promote Ptolemy’s geocentric tradition, their European counterparts began a new astronomy based on Copernican heliocentrism. The interconnectedness between Islamic and European astronomy was largely a product of increased competitiveness, an eagerness to assert the superiority of their sciences, and a fear that the post-Copernican period would mark the end of the Islamic golden age. The parallel discoveries at the Istanbul and Uraniborg observatories demonstrate how two different intellectual cultures were tied together by celestial phenomena, despite being separated by a cultural chasm. 

The Uraniborg Observatory was operated by Tycho Brahe, a notorious Danish astronomer, under the sponsorship of King Frederick II of Denmark. Located on the island of Hven, its main purpose was to conduct astronomical observations. However, Tycho also used the building to house his alchemical laboratory. The building itself was made in a Flemish Renaissance fashion with sandstone and limestone frames and it overlooked an impressively geometrical garden. Essentially, the observatory was a heavily ornated piece of architecture that complimented Tycho’s stylish lifestyle; however, its magnificent exterior was not the only impressive feature of the institution. Uraniborg accommodated a variety of astronomical instruments, some old, and some invented by Tycho himself. While he was portrayed as ‘detached’ from his Islamic predecessors and the Ottoman Empire, this was far from the truth. He relied on several astronomical instruments which originated in the Islamic world including the Quadrant and Armillary Sphere. Therefore, it can be argued that his astronomical developments supplied a thread of continuity rather than a distinct split from medieval Islamic astronomy.  

The Istanbul Observatory, built in the same decade as Uraniborg, served the same purpose. Yet it was also believed that its construction would revive the superiority of Islamic astronomy which had been slowly declining in the 1500s. Persian poet Ala al-Din al-Mansur critiques in his Book of the King of Kings the astronomical tables of medieval astronomers such as Ulugh Bey and Nasir al-Din Tusi, suggesting that they had become ‘worn-out like traces of mats upon soft soil.’ The question of who pushed for the construction of the new observatory remains unanswered, but from Al-Mansur’s work it seems that it was Sultan Murad III’s who issued ‘orders for making observations and compiling astronomical tables.’ There is no doubt that this decision was encouraged by Egyptian scientist Taq al-Din, who subsequently became the chief astronomer of the observatory and strove to better the astronomy of the Middle Ages. Described as the ‘Tycho Brahe of the Ottoman Empire’, al-Din produced new astronomical instruments alongside his staff which included twelve captured Christians. Here we can begin to see indications of the cross-cultural interaction between the Istanbul Observatory and Europe in general. Another example can be observed in al-Mansur’s miniatures, which depict a comet observed in 1577 by the observatory, which was similar to European paintings of the same comet.  

The comet discovered in 1577 was a critical event for both observatories; a celestial phenomenon that was interpreted in different ways by Tycho Brahe and Taqi al-Din, the leading astronomers of the sixteenth century. The comet reveals a large deal about the ways in which the observatories operated and their purpose. Tycho interpreted the comet as a signpost in his career, a turning point that motivated him to leave behind ancient Ptolemaic tradition. With this mindset, he was able to observe the comet’s behaviour for the remainder of his life and noticed that its trajectory through the heavens disproved Aristotle’s theory of crystalline spheres. While Aristotle wrote that between stars lay ‘spheres’, which kept them in their rigid frame, Tycho was able to prove otherwise with the comet, and recorded this new observation in his 1588 treatise. 

It was undoubtedly Tycho’s mindset to challenge ancient theories that gained him the reputation as the best astronomer of the pre-telescopic world. In contrast, the comet foreshadowed an Ottoman victory over the Safavids, thus confirming the value of the newly built Istanbul Observatory. Evidently, the comet’s meaning differed between the two institutions, with it being a validation mark for the Ottomans and having longer-term effects for Europe. Perhaps the reason behind this is the unfortunate decline of the Istanbul Observatory, which was torn down on the order of Murad III in 1580 under increased pressure from religious courtiers who opposed astronomical studies. Details of the incident were described by al-Mansur, who stated that ‘the enemy [those who did not support the observatory] is dying of grief,’ therefore the observatory was bound to fail without the support of the Ottoman court. Conversely, Tycho’s observatory was continually supported by the Danish King and landed more security.  

Notably, the level of modernity between the two observatories did not differ a great deal. Both were state of the art observatories in the Eurasian world and used similar astronomical instruments. The armillary spheres at both institutions featured six rings of the same measurement and they also had identical dioptre. Had the Istanbul Observatory survived, it may have even surpassed the advancements of Uraniborg, especially if Taqi al-Din remained chief astronomer. Obsessed with mechanical cosmology, Taqi favoured a wider trend of describing nature as a machine, inspired by European mechanical clocks and automata. He was the first Islamic artisan to build a mechanical clock in the Eastern Mediterranean which he titled a bankamat in Arabic. He also produced a manuscript with illustrations on how to build clocks that would increase astronomical precision. Taqi even believed that mechanics possessed the power to change the cosmic order and attempted ‘to build a machine and a clock that would reflect the spiritual structure of the heavens.’ Notably, his tampering with ‘impious cosmology’ perhaps also contributed to the observatory’s downfall. Nonetheless, Taqi’s determination to build increasingly precise mechanical clocks may have placed the Istanbul Observatory above Uraniborg had it survived after 1580.  

The most noticeable link between the two observatories lay in the various apocalyptic sentiments shared by the Ottomans and European powers. In the mid-sixteenth century, Tycho Brahe predicted the death of Sultan Suleyman the Magnificent. In contrast, the Sultan prophesied the coming of the Antichrist for Christians. The apocalyptic visions of these differing cultures essentially predicted one another’s doom. With the death of Suleyman in 1566, it looked as though the sky was favouring the Europeans. Such prophecies that originated from the sky may have also stimulated Murad III to order the construction of the Istanbul Observatory in an effort to change the cosmic order. Thus, the Istanbul Observatory may have been constructed for the heavens to shift in favour of the Ottomans in this battle of prophecies. From this example, it is evident that the rivalry between the two institutions was dialectical – the observatories did not follow separate paths but were in a constant exchange.  

Many links can be identified between the two observatories, and both are fantastic examples of the cross-cultural interactions of the early modern period. Taqi al-Din and Tycho Brahe were both ambitious astronomers who aimed to improve the accuracy of astronomical tables and, as aforementioned, may have continued to be worthy rivals if it had not been for the Istanbul Observatory’s destruction. The astronomical instruments of the two observatories were largely similar, and there was a motivation on both sides to develop better clocks and other mechanical devices that would potentially substantiate or disprove popular astronomical theories. It is also important to consider these two observatories as unique from another, given that they were constructed in different cultural contexts – this study aimed to emphasise the interconnectedness of astronomy in the early modern period and the shift in the dominance of astronomy from the Islamic world to Europe. While it is not known whether the observatories were linked directly, it is interesting to assess the parallels between them. 


Ben-Zaken, Avner. Cross-cultural Scientific Exchanges in the Eastern Mediterranean, 1560-1660. Baltimore: Johns Hopkins University Press, 2010. 

Blake, Stephen P. Astronomy and Astrology in the Islamic World. New Edinburgh Islamic Surveys. Edinburgh: Edinburgh University Press, 2016. 

UNESCO. ‘Outstanding Astronomical Heritage Description.’ [Online]. [Accessed on 11 April 2021].  

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