London, 14-17 Sept. 2018: “Stabilities and innovations in the astral sciences: perspectives from Chinese, Sanskrit, Arabic, and Latin sources”

In the context of ESHS Conference London

14-17 Sept. 2018


  • Anuj Misra (Postdoc TAMAS project, PSL-Paris Observatory- SYRTE, France)
  • Li Liang (Beijing Institute for the History of Natural Science, Chinese Academy of Science, China)
  • Matthieu Husson (CNRS, PSL-Paris Observatory-SYRTE, France)

This symposium is prepared with the support of the ERC project ALFA (agreement n°723085)


It is often a tacit belief in the study of history of science that habitual and customary practices are of lesser interest than innovations and novelties. The agency and creativity of historical actors are supposed to chiefly required for innovations, whereas the stability of their practice implied some sort of passivity. This view also usually implies that innovation need to appear against or in spite of conservative forces. In contrast, we want to explore a more dialectic interpretation of stabilities and their relations to innovations, by investigating questions such as:

  • What are the particular knowledge elements that remained stable in given context of scientific practices?
  • What kind of active choices and concrete actions endorsed by historical actors allow those knowledge elements to remain stable in a given context of practices?
  • How do these efforts to maintain stability of specific knowledge elements allow historical actors to investigate reconfigurations of other aspects of their scientific practices?

We hope to substantiate the view that there is a plurality in the ways of a scientific practice to select and retain a specific set of knowledge elements as stable within a given context; and to use them to explore other possibilities of reconfigurations and innovations. For instance in Alfonsine astronomy, during the late medieval period in Europe, astronomical parameters remained stable for almost two centuries while the layout and organisation of tables varied a lot. We expect to address these general methodological issues in the history of science from case studies in the development of the astral sciences in Arabic, Sanskrit, Chinese and Latin sources. While astral sciences is not the only field of exploration for these questions, it certainly offer a promising start to this endeavour. For instance

Astronomical practices involve a range of knowledge elements from fundamental mathematical ones like numbers or geometrical objects to more global ones like epistemological values expressed, for instance, in cosmological theories, observations, or reasoning practices. The material cultures of astronomical practices are also quite diversified. Multiple different kinds of instruments are known to be used and various different form of texts are available to us, for example: oral texts (prose or verse), numerical tables, technical diagrams, iconography, etc. Moreover, the practices of astral sciences were often socially distributed across various milieus. These ranged from highly specialized individuals working in intellectual, political or religious institutions to more modest practitioners engaged with astronomy in some specific and limited way. In this way, the field of astral sciences offers a choice of relatively well-connected historical contexts necessary to explore these issues, while at the same time, it provides a topical focus to compare various case studies in a meaningful and effective manner.

(alphabetical order)

  1. BRENTJES Sonja (Max Planck-Berlin, Germany) Arabic sources
  2. CHEMLA Karine (CNRS, SPHERE, France) Chinese sources
  3. FECKE Jackie (Waterloo university, Canada)
  4. HIROSE Sho (Postdoc, ETH Zürich, Switzerland) Sanskrit sources
  5. HUSSON Matthieu (CNRS, PSL-Paris Observatory-SYRTE, France) Latin sources
  6. KNUDSEN Toke (University of Copenhagen) Sanskrit sources
  7. LI Liang (Beijing Institute for the History of Natural Science, Chinese Academy of Science, China) Chinese sources
  8. LOIZELET Guillaume (postdoc –SPHERE, France) Arabic sources
  9. MINKOWSKI Christopher (Faculty of Oriental studies-University of Oxford, England) Sanskrit sources
  10. MIOLO Laure (Postdoc ERC ALFA, CNRS-Paris Observatory-SYRTE, France) Latin sources
  11. MISRA Anuj (Postdoc TAMAS project, PSL-Paris Observatory- SYRTE, France) Sanskrit sourcres
  12. PIETRONI Silvia (PhD ERC ALFA, CNRS-Paris Observatory-SYRTE, France) Latin sources
  13. MOUSAVI Razieh (PhD, Max Planck Berlin,Germany) Arabic sources
  14. SAMSÓ Julio (Universitat de Barcelona, Spain) Arabic sources
  15. GUANGCHAO Wang (University of Chinese Academy of Sciences, China) Chinese sources
  16. WEIL Dror (Postdoc, Max Planck Berlin, Germany) Chinese sources

Session 1


Liang Li
(Beijing Institute for the History of Natural Science, Chinese Academy of Science, China)

New astronomy served the old astrology: The calculation of lingfan in the early modern China

The astronomical phenomena lingfan 凌犯 (literal meaning encroachment; the occultation and conjunction among the moon, the five planets and the fixed stars) plays an important role in both Chinese traditional astronomy and astrology. China has a long tradition to record the history of last dynasty known as official standard histories, and the astronomical part “Monograph on astronomy” in the official standard histories has a routine to record the lingfan in history. However, the Chinese traditional calendrical astronomy could not solve the problem of planetary latitude, so it was impossible to predict the phenomena of lingfan in advance, and the corresponding astrology was always done after such portents were discovered through actual observations.

In the fourteenth century, after the adoption of Islamic Huihui lifa in China, this puzzle was eventually solved. With the assistance of the Islamic method, a kind of ephemeris listing the daily prediction of lingfan turned up, and to submit these ephemeris to the emperor annually became a custom from then on. Even though the Chinese used the innovational Islamic method to calculate the lingfan, they still referred to the Chinese traditional astrology but not the corresponding Islamic astrology to explain the portents. With the Jesuits introducing western astronomy into China in the sixteenth and seventeenth centuries, the Chinese began to revise the method of predicting lingfan with the new European astronomical methods and to update the procedure of the ephemeris compilation. This paper will discuss how the Chinese astronomers tried to solve the problem of lingfan flexibly with the innovational foreign methods, and to what extent they followed the unchanging tradition.  


Silvia Pietroni
(PhD ERC ALFA, CNRS-Paris Observatory-SYRTE, France)

Equation of Time in Alfonsine Astronomy

Throughout time not very many astronomical tables kept evolving. However, some did, as is the case of the table for the equation of time, where the parameters underlying it were often modified but the format of the table remain basically unchanged for many centuries. In this presentation we offer a general survey of the evolution of the equation of time through these traditions analysing from manuscripts ancient and medieval texts and tables We will find out the differences in their pattern and calculate the eventual unknown underlying parameters through statistical methods. Alfonsine astronomy provides examples of the equation of time, which will be the object of this presentation.


Sonja Brentjes
(Max Planck-Berlin, Germany)

On the uses of anthropomorphic images of star constellations in Islamicate societies

In my talk, I will discuss major forms of use that the anthropomorphic images of star constellations in ‘Abd al-Rahman al-Sufi’s respective book have served in different material setting and socio-cultural contexts. I will reflect on the relationship between astronomical and art practices, royal gift giving, education, legitimation and representation of power, and artisanal skills.


Guillaume Loizelet 
(postdoc – SPHERE, France)

Distances of wandering stars to Earth: Al-Bı̄rūnı̄’s diachronic approach

In Chapter 6 of book X of his Qānūn al Mas`ūdı̄, Al-Bı̄rūnı̄ adresses the problem of distances of wandering stars to Earth. Reviewing and discussing on his greek, indian and arabic predecessors works, Al-Bı̄rūnı̄ endorses an historical point of view and thus let us investigate on what is stable and what is not in this peculiar field. I intend to utilise chapter X.6 as a generic example in regard both to permanence of cosmological views Al-Bı̄rūnı̄ stated and to the selection of specific points he elected as questionnables.


Session 2


Anuj Misra
(Postdoc TAMAS project, PSL-Paris Observatory- SYRTE, France)

The distribution and organisation of astronomical ideas in Sanskrit canonical texts

Looking at the contents of most canonical texts (siddhānta) in Sanskrit astronomy (jyotiḥśāstra), we notice a relative systematic arrangement of topics into various chapters (adhyāya or adhikāra). Each of these chapters addressed particular aspects of mathematical astronomy like mean and true positions, eclipse computations, terrestrial geography and cosmography, spheres, etc. and in most instances, the arrangement (ordering) of these chapters in the siddhāntas remained fairly uniform and standard. It is in this context that I explore how early seventeenth century Sanskrit astronomers like Nityānanda (Sarvasiddhāntarāja 1639 CE), Munīśvara (Siddhāntasārvabhauma 1646 CE), and Kamalākara (Siddhāntatattvaviveka 1658 CE) discussed, distributed, and organised newer Islamic (Ptolemaic) `knowledge elements’ within the topical framework of siddhāntic chapters.


Karine Chemla
(CNRS, SPHERE, France)


Laure Miolo
(Postdoc ERC ALFA, CNRS-Paris Observatory-SYRTE, France)

Stabilities and innovations in John of Genoa’s Opus astronomicum

This paper aims to situate John of Genoa’s astronomical treatises in the Parisian scientific practices of the first half of the 14th century and its intellectual context. Little is known about John of Genoa, he was probably a disciple of John of Lignières to whom he borrowed a lot of material. Several evidences indicate that he was a scholar of the University of Paris in the 1330’s. He was certainly involved with the group of astronomers comprising: John of Lignières, John Vimond, John of Saxony and John of Murs. This period can be considered as a time of development and innovation in the field of Alphonsine astronomy. Of course, Alphonsine astronomers continued to be deeply indebted to older theoretical and practical sources. The case of John of Genoa is quite significant. He wrote several astronomical works mainly related to eclipses and the motion of the Sun, the Moon, based on Alfonsine tables for the meridian of Paris. His best known treatise is a canon on eclipses dated to 1332, extant in six manuscripts. It is based on three important astronomical works, which constituted sources for pre-Alphonsine astronomers : the Almagestum parvum, Albategni, De scientia astrorum and John of Sicily’s commentary on Toledan Tables. Likewise, his short canon on Solar and Lunar motions is based on Albategni’s zij. A close study of John of Genoa’s works should lead to encompass what was the intellectual background of this scholar and in which milieu he was included.


Toke Knudsen
(University of Copenhagen)

Continuity Amidst Change in India ca. 1500 CE

When Jñānarāja wrote the Siddhānta-sundara, a Sanskrit astronomical treatise, around 1500 CE, three-and-a-half centuries had gone by since Bhāskara II wrote the Siddhānta-śiromaṇi in 1150 CE. In the treatise, Jñānarāja presents a critique of his astronomical tradition, rejecting certain ideas, such as that the earth is its own support and that down is relative to your location on the earth, connecting his treatise to a group of obscure astromomical texts claiming divine origin. But even with Jñānarāja’s attempts at revising the foundations of the science of astronomy, the basics of its execution remained unchanged. The talk will examine the points of Jñānarāja’s critique with an eye to the elements of the tradition that remained stable in his treatise.


Comments by Richard Kremer
General discussion 1



Session 3


Christopher Minkowski
(Faculty of Oriental studies-University of Oxford, England)

The Philosophy of Foundations and the Exact Sciences in Sanskrit

David Pingree once remarked that the exact sciences in Sanskrit – astronomy, astrology, and mathematics – were advanced by a conspicuously small number of original thinkers, who operated in an intellectual setting that was not tightly connected with other, more prestigious systems of knowledge in Sanskrit. Indeed, while Indian authors in logic and exegetical theory (Nyāya and Mīmāṃsā) the philosophical systems most concerned with what constitutes good reasons, began their texts with consideration of its foundations and with extended rationales for the practice of their discipline, it appears that the astronomers did not feel it necessary to include a discussion of their science’s philosophical basis. The methodological passages of the most intellectual astronomical texts, the siddhāntas, may identify the questions to be answered – relative positions, conjunctions, eclipses and so on. They may cover spherics and some principles of the motions of the luminaries in circles and epicycles, but they offer no justification for the science beyond making claims about utility and accuracy. The same situation obtains in the astrological compendia (saṃhitās), where little justification is offered for the predictive reliability of the science.

In the early modern period this changed. Astronomers and astrologers alike began to include just such discussions in their works. Even before that, however, the ‘high’ philosophical traditions in Sanskrit, though reticent on the exact sciences, did attempt to classify the nature of their validity as a form of authoritative knowledge. In this talk I will consider some passages in Mīmāṃsā texts, especially in the work of Kumārila Bhaṭṭa and his commentators, and some passages of texts in Nyāya and Sāṃkhya. I will discuss what these passages meant for the intellectual history of the exact sciences, and the reasons for jyotiṣas’ evident confidence in the legitimacy of their discipline.


Jackie Fecke
(Waterloo University Canada)

The Physics of Ptolemy’s Astrology

In his astrological text, the Tetrabiblos, Ptolemy describes celestial bodies as transmitting their powers through the heavens and into the sublunary realm.  The way they do this is by means of rays.  Ptolemy no where states what these rays consist of, if anything, or how the stars transmit them, and yet they bring the powers of the stars into contact with one another as well as with sublunary bodies and souls.  It is because the stars’ rays come into contact with the elements comprising the sublunary region that the stars and their movements effect changes there, including meteorological phenomena and even the characteristics of human souls.  In this paper, I will explore the nature and movements of these celestial rays by drawing on Ptolemy’s physical theory as portrayed in the Tetrabiblos as well as his On the Kritêrion and Hêgemonikon, Planetary Hypotheses, Optics, and fragments from his lost On the Elements.  I will argue that Ptolemy may have adjusted his element theory in order to maintain the consistency of the astrological theory of rays with his physics.


Matthieu Husson
(CNRS, PSL-Paris Observatory-SYRTE, France)

On John of Saxony comments’s to John of Lignères Cujuslibet arcus…: Stabilities and innovations in a (pedagogical) commentary practice

John of Lignières and John of Saxony were two important Parisian astronomers in the first half of the 14th c. The first wrote an encyclopaedic set of Canons and tables in the early 1320 (canons dated 1322, epoch dates of tables 1321) inspired from Albattani but also introducing then relatively new Alfonsine ideas in Latin. These alfonsine ideas had then a great success and progressively became dominant in Europe up until the 16th c. This success is attested also by the numerous manuscripts copies of another set of Canons to the Alfonsine tables wrote in 1327 by John of Saxony who was trained to mathematical astronomy by John of Lignères. Several manuscripts sources provide evidence of this pedagogical relationship between the two astronomers. More precisely we are going to look at the chapter on shadows of the canons of John of Lignières and at two types of comments produced by John of Saxony on them. The first are very close to the redaction of the treatise and the second, more systematic were produced more than 10 years later. The differences in the material presentation of the comments, the content they point to in the commented text, the way they extend, precise or interrogate it, will be clues to explore how stabilities and innovations are related at a micro-level in this particular situation.


Sho Hirose
(Postdoc, ETH Zürich, Switzerland) Sanskrit sources




Session 4


Julio Samsó
(Universitat de Barcelona, Spain)

Tradition and innovation in Western Islamic astronomy

Although depending on an Eastern input which arrived to al-Andalus until ca. 950, a moment in which the connection with Eastern Islam was interrupted, Andalusian astronomy became highly original in the 11th century. My talk will deal with the following topics:

  • A correct determination of the length of the Mediterranean, through the use of the water meridian. This took place towards the end of the 10th c., probably as a result of an observation of a lunar eclipse in Córdoba, which was compared to a computation of the same eclipse using al-Khwārizmī’s zīj.
  • The theoretical innovations introduced by Ibn al-Zarqālluh (Azarquiel) (d. 1100): trepidation theory, motion of the solar apogee, solar model with variable eccentricity, correction to the Ptolemaic lunar model. All these innovations were introduced and developed in the Maghrib in the 13th and 14th c.
  • The survival of a Khwārizmian tradition which used sidereal mean motions, as opposed to another tradition of tropical astronomy, both in the Iberian Peninsula and in the Maghrib. The introduction in the Maghrib of tropical Eastern zījes from the 14th c. onwards.


Razieh Mousavi
(PhD, Max Planck Berlin,Germany)

Al-Farghānī’s Elements of Astronomy, an innovative presentation of Ptolemaic astronomy?

The astronomical treatise of al-Farghānī (ca. 805-870 A.D) mostly known as the Elements of Astronomy (or Kitāb fī al-Ḥarakāt al-Samāwīya wa- Jawāmiʿ ʿilm al-Nujūm) was composed after the death of Maʾmūn (ʿAbbāsid Caliph) in 833 but before 857 A.D. This book was quite popular in Arabic, as testified in part by the numerous surviving manuscript copies. Al-Farghānī’s Elements of Astronomy gives a comprehensive account of Ptolemaic astronomy in an entirely descriptive and non-mathematical method. These features, together with clarity and conciseness, might have been responsible for the enormous popularity of this book both in Islamic and European history of scholarship. It is a short introductory presentation of astronomy based on Ptolemy’s Almagest, comprising thirty chapters.

On one hand, the Elements of Astronomy¬ remained within the framework of the astronomical models proposed by Ptolemy in Almagest regardless of some updates in parameters. As a result, al-Farghānī’s compendium was often characterized as a compilation of selected parts, or in one sense, a summary of Ptolemaic astronomy. On the other hand, special features of describing astronomical notions including intentional selections of Ptolemaic astronomy, support the idea of making Elements of Astronomy more in line with what we know as the hayʾah tradition. This trace of innovation despite the loyalty to the principles in writing Elements of Astronomy will be briefly discussed in this paper. Accordingly, the stability and deviations of Almagest will be explored in al-Farghānī’s Elements of Astronomy through methods of presentation and classification of Ptolemaic astronomy.


Wang Guangchao
(University of Chinese Academy of Sciences, China)

A Chinese effort to determine the solar model in the 18th century: the case of the Lixiang kaocheng

Ancient Chinese mathematical astronomy in its maturity was generally described as independent with the assumptions about the real motions of the physical luminaries. It was not until seventeenth and eighteenth centuries Chinese astronomy experienced a conceptual revolution under the influence of Western astronomy. Western astronomy, which Jesuit missionaries introduced during that time, had a more pervasive and profound influence on Chinese astronomy. Chinese native astronomers adopted Western mathematical methods from their Jesuit colleagues, they shifted their original paradigm from numerical and algebraic procedures to geometric model. This change allowed them not only to predict but also to explain astronomical phenomena. The solar model which adopted in Lixiang Kaocheng provides a concrete example of the way how Chinese domestic astronomers deal with computation and observation. Different with the eccentric solar model in Xiyang Xinfa Lishu,Kaocheng used the double epicycle model considering that the computation should be in agreement with the observation. Though it was a big apparent change from eccentric model to double epicycle model, but the accuracy of the data computed from the solar model did not increase largely compared with the previous calendar. Moreover, it has been found that the observational data which was the basis for computing the parameters of the solar model were so accurate that the astronomical instruments could not reach. These data probably come from the calculation result of extant western astronomical tables.


Dror Weil
(Postdoc, Max Planck Berlin, Germany)

Stabilities and innovations through Translation: The Fourteenth-Century Naturalization of Arabo-Persian Astronomy in China

We tend to think of translation in terms of change in language or media. However, translation projects can represent political attempts to preserve older systems and useful knowledge for the sake of maintaining political stability. The case of the naturalization of Arabo-Persian astronomy in China during the late-fourteenth century illustrates the two effects of translation.

The proposed talk discusses the first Ming emperor’s project of translating and naturalizing Arabo-Persian astronomical knowledge during the second half of the 14th century, amid the sociopolitical transition from the Yuan to the Ming dynasties. It will show how the translation of Arabo-Persian astronomical texts into Chinese served the Ming ruler in his ideological oscillation between preserving the Yuan institutions and creating new ones. Translation, I argue, enabled the first Ming emperor to display his disengagement from the institutions of the former Mongol rule, and at the same time to benefit from the astronomical accomplishments of the Yuan. By charting the attitudes of the newly established Ming dynasty toward the use of Arabo-Persian astronomical knowledge, the proposed talk points to continuities and ruptures in the accommodation of astronomical knowledge at the Chinese court. Looking at how the Ming court accommodated Arabo-Persian astronomical knowledge by creating continuities and innovations in the application of court astronomy, I will use this case how Ming China entangled politics and knowledgeproduction processes and its attitude towards foreign knowledge.

General discussion 2