Paper Instruments in the History of Ottoman Astronomy, by Gaye Danışan

This project was born from an idea that several specimens of Ottoman astronomical calendars could also be a subject of paper instrument research. Therefore, the primary purpose was to provide an overview of paper instruments in Ottoman astronomy, a neglected topic up to date. Thus, the study first focuses on identifying Ottoman paper instruments without period limitation, then the classification and analysis based on their variety, usages and periods.

At the beginning of the research, we started with following three specimens: An Ottoman volvelle found in Rûznâme-i Şeyh Vefâʾ [replicated in 1676, BnF supplément turc 537]; an annual calendar drawn on cardboard by Derviş Mehmed el-Hasib el-Mevlevi [Kandilli Observatory and Earthquake Research Institute, MS 540, copied 1134 H. (1721-22 CE); hereafter KOERI], a quartier de reduction (sinical quadrant) used among French mariners with the name of serko haritası in an Ottoman book on navigation entitled Navigasyon (1857). Some details for these specimens were given in a previous blog. Now, other specimens have also been included in the project.

The first example is a gurrenâme in circular form with moving part which allows one to find the day of the week corresponding to the beginning of each lunar months for the year 1096 H. [(1685 CE); Gurrenameler mecmu‘ası, KOERI, MS 116, fol. 8v.]. We can understand how to use this gurrenâme from explanations above and below the circle. The second example is another volvelle related to the week’s day corresponding to each lunar months. However, it is uncompleted, or it has some missing parts. This volvelle is found in a perpetual calendar whose precise date is unknown, but it includes a gurrenâme in tabular form, covering the years from 1073-1085 H. [(1662-1674 CE); Gurrenâme, Bursa Inebey Manuscript Library, Orhan Collection, MS OR2084/2, fol. 62r.]. Thus it may be inferred that it is an example of 17th-century calendars. The third example is a volvelle to convert the Arabic, Persian and Coptic calendars (Fig. 1). It is found in a manuscript on preparing a calendar, which is anonymous, and unknown date [Risala fi istihraç at-tavarih, KOERI, MS 180/12, folio 82r.]. The fourth specimen is a circular form without moving part to determine the time of sâlat el-‘îd (Prayer of the eid) corresponding to the year 1251 H. (1835/36 CE). It was found from the digital catalogue in a manuscript about a legend entitled Menakıb-ı Şeyh Ebü’l Vefa which was prepared in 1293 H. [(1876 CE); Suna ve İnan Kıraç Foundation Manuscript Collectşon, MS SR000315, fols. 53v-54r]. The paper instrument is not attached to it. Besides, the different dates between paper instrument and manuscript made us think whether this calendar is a part of the manuscript. Unfortunately, now, the paper instrument is not in this manuscript. It could have been put in a different manuscript, or it could have been lost.

Another example is especially interesting because it reminds of gunner’s rule, which Bombardiers (Humbaracı) used to measure artillery piece elevation. It was called by the following terms: mizan-ı humbara, alet-i irtifa, humbara terazisi, kantar terazi or just terazi . However, this paper instrument is found in a corpus of treatises on lunar mansions, calendar conversion tables, perpetual calendar and ahkâm text which was prepared by Ahmed Lütfullah el-Mevlevi who was a müneccimbaşı (chief astronomer) between 1660 and 1668 (Süleymaniye Library, MS 1027/1, fol. 63v). The paper instrument is not attached to this corpus, and the precise date of the paper instrument is unknown. Besides, its structure and small size do not allow one to use it for military purposes. Thus it might have been designed for educational purposes.

The last surviving example is a celestial map entitled Miratü’s-semâ (the mirror of the sky) (Fig. 2, KOERI, No. 223). On the celestial map, there is a note that Tahsin prepared the visibility of celestial sphere for the most of Ottoman lands. We know that Hoca Tahsin Efendi (Hasan Tahsin, d.1881), one of the most prominent scholars of the Ottoman Empire of the 19th century, prepared a celestial map since Bursalı Mehmed Tahir (d.1925) mentioned him in his book entitled Osmanlı Müellifleri[1]. The note on the celestial map also matches up with the passage on Hoca Tahsin Efendi in the Bursalı Mehmed Tahir’s book. Thus, the name of Tahsin may point out Hoca Tahsin Efendi.

On the other hand, during this research, we encountered circular diagrams related to calendars onAhmed b. Süleyman et-Tancî’s portolan (1416), Mürsiyeli İbrahim’s portolan (1461) and el-Hacc Ebu’l Hasan’s portolan (1552?), and some manuscripts especially discussing on perpetual calendars. I did not count them in the scope of the project because these examples are controversial in terms of whether the contents of a circular drawing related to calendar systems will be evaluated in the category of paper instruments. However, I think over these diagrams because of their similar context with volvelles related to calenders. Besides, few examples mounted on wood such as Hoca Tahsin’s portable sundial made in Paris in 1867 are not included in the project. 

The method and results of the project will be shared with full detail in a subsequent issue of the Bulletin. I hope this project would shed light on paper instruments in the history of Ottoman astronomy.

[1] Bursalı Mehmed Tahir Efendi, Osmanlı Müellifleri, edited by A. Fikri Yavuz, İsmail Özen, Meral yayınevi (İstanbul, 1972), Vol. I, pp. 346–347.