A Comparative Study on the Theoretical and Practical Aspects of Scientific Activity in the Ottoman Empire: Annual and Perpetual Calendars (1550-1710)
This project was supported by the TUBITAK 1003 Priority Areas Support Program between 2020-2022.
ABOUT THE PROJECT
Calendars, which constitute a significant part of Ottoman scientific literature, are valuable sources not only for the history of science but also for various other fields, such as philosophy, folklore, medical history, and environmental history, due to their vast array of information covering topics from astronomy to astrology, meteorology to natural sciences, health to nutrition, and religious beliefs to philosophy. However, the comparative study of these sources’ theoretical and practical aspects over a long period has been a neglected topic in the history of science. In this context, within the framework of the TUBITAK-1003 Research and Development Projects Support Program, the project titled “A Comparative Study on the Theoretical and Practical Aspects of Scientific Activity in the Ottoman Empire: Annual and Perpetual Calendars (1550-1710)” aims to shed light on the scientific understanding manifested in Ottoman calendars, determine the relationship between the calendar makers and users, and investigate the place of calendars in the historiography of science. As part of the project, three types of calendars produced in the Ottoman territories between 1550 and 1710 are being examined. One of these is the annual calendar (takvîm-i sâl), presented to the sultan by the chief astronomer (müneccimbaşı) every year on Nevruz (around March 21st). The second type consists of prognostication for the ascendant of a year (aḥkâm-ı ṭâli‘-i sâl), which typically contains predictive interpretations of events expected to occur in the upcoming year, often based on astrological prognostications made according to the positions of celestial bodies. The third type of calendar to be examined within the project is the perpetual calendar (rûznâme, takvîm-i dâimî or takvîm-i devr-i dâimî), designed for long-term use.
These types of calendars are analyzed in two aspects. The first is the analysis of the theoretical aspects of annual and perpetual calendars. For this purpose, it is aimed to reveal the background of the basic mathematical and astronomical principles of aforementioned calendars, such as the changes in the lunar, seasonal and day-night periods; the determination of weeks and days, and the determination of the basic principles of date conversion. In line with this objective, the analysis will reveal how some celestial events (such as planetary conjunctions, comets, solar and lunar eclipses) occurred between 1550-1710 were included and interpreted in Ottoman calendars. For this purpose, various astronomical programs such as Stellarium and NASA’s astronomical catalogue are used to check the accuracy of these astronomical data and to determine the scientific value of the calendars. Researchers use this method in recent studies on the history of astronomy. In addition, the findings obtained from calendars are also compared with the results of studies on astronomical science developed in the West from the 16th century onwards. This allows us to evaluate the process of transferring and adapting the astronomical science developed in the West from the 16th century onwards to the Ottoman civilization through calendars.
Image 1. H. 983 (1576-1577) senesi, Zilhicce ayının dokuzuncu gününe ait zayiçe (Takvîm li-sene 983, Istanbul University Library of Rare Books, TY200, 25a)
Image 2. Hüseyin Efendi, Aḥkâm-ı ṭâli‘-i sâl ve taḳvîm (H. 1055-56/1645-46), Kandilli Observatory and Earthquake Research Institute, History of Science Collection, MS. 165/3, 32a.
Thus, the identification of the astronomical and mathematical methods used by Ottoman scholars in the preparation of calendars and the comparative analysis of the scientific and philosophical aspects of different scholars who prepared the calendars contribute significantly to the comprehension of the processes of scientific interaction in the Ottoman Empire and the understanding of science.
On the other hand, our question about the relationship between the calendar makers and the calendar users is related to examining the practical aspects of calendars. In this context, historical notes on astronomy, meteorology, medicine, agriculture, etc., are analyzed to determine the relationship between the information in the calendars and the calendar users. Furthermore, information about agriculture, meteorology, navigation, etc., identified through the analysis of calendars, is also compared with primary source materials other than calendars. This methodology enables us to establish a connection between the historical context and Ottoman calendars.
In sum, instead of a single calendar sample, this project comparatively analyzes many calendars with their theoretical and practical aspects over a long period. Besides, it evaluates the attitudes and differences of Ottoman scholars in the scientific tradition and the changes in the field of science and philosophy throughout the period on these calendars.
Image 3. Şeyh Vefa, Ruznâme-i Şeyh Vefâ, Kandilli Observatory and Earthquake Research Institute, History of Science Collection, MS. 114, 1b.
Image 4. The first European edition of Şeyh Vefa’s perpetual calendar. Georg Hieronymus Welsch: Commentarius in Ruzname Naurus : sive Tabulae aequinoctiales novi Persarum et Turcarum anni, 1676.