Flora Vafea | Al-Azhar University (original) (raw)

Conference Presentations by Flora Vafea

From Alexandria to Al-Iskandariya, 2021

The astrolabe was the most widespread astronomical instrument from the Greek-Roman period to the ... more The astrolabe was the most widespread astronomical instrument from the Greek-Roman period to the end of the Middle Ages
and the beginning of the Renaissance. Among the most important treatises on the use of the astrolabe was those written by the
astronomer 'Abd al-Raḥman al-Ṣūfī (903-986AD).
In this paper, the outline of the 3 treatises of al-Ṣūfī on the astrolabe is presented, with a focus on the description of the
construction of the almucantars on a plate of the astrolabe, and the calculation of the distance between two cities using the
astrolabe. There is also a comparison between the 3 versions.
The work of al-Ṣūfī on the astrolabe inaugurated a new era in the study of the instrument. The preserved treatises on the use of
the astrolabe before al-Ṣūfī are short and elementary. Al-Ṣūfī tried to compile complete and detailed treatises, not only
including and systematizing the previous knowledge, but also correcting the errors of the former authors and expanding the
use of the astrolabe to thousands problems included in his treatises.

The Antikythera Mechanism is the most sophisticated extant ancient astronomical instrument and an... more The Antikythera Mechanism is the most sophisticated extant ancient astronomical instrument and analogue computer known and was assembled sometime between 150 and 100 BCE, almost a century after the death of Archimedes. The mechanism has a great educational potential as it appeals to inquiring minds as an astonishing artefact of science and technology. The latest research findings reveal significant cultural and social functions in its operations. This astonishing astronomical instrument has a clear interdisciplinary valueand it has that it may be used as an educational medium, to engage the general public, and especially to attract students both to/from exact sciences and to/from the humanities. The astronomical and technical knowledge embedded in the mechanism can also be used to introduce some aspects of modern science through the unknown technological achievements of Hellenic antiquity.

Papers by Flora Vafea

Suhayl. International Journal for the History of the Exact and Natural Sciences in Islamic Civilisation, 2016

This paper focuses on an extract from the treatise of al-Bīrūnī (973-1048 AD) Comprehension of th... more This paper focuses on an extract from the treatise of al-Bīrūnī (973-1048 AD) Comprehension of the possible ways for the construction of the astrolabe, where “the plate of the eclipses” is described. This is a device that can be attached on the back side of the astrolabe. It consists of a plate, engraved on both sides, and a grid that can be attached to either side of the plate and can rotate upon it. Given the date of the lunar month, one can find the time of the moon rising and the phase of the moon, using the front side of the plate. Knowing the latitude of the moon at the opposition, one can determine whether there will be a lunar eclipse or not, using the back side of the plate, and can also estimate the magnitude, start time and duration of the eclipse. The results are approximate.

Speaking about classical studies, we usually mean the study of ancient Greek and Latin literature... more Speaking about classical studies, we usually mean the study of ancient Greek and Latin literature, history, and philosophy that has come to us through the magnificent works of distinguished ancient writers. But a characteristic feature of Greek Philosophy was the consideration of the world and the ideas as one entity that cannot be studied separately. Thus, the Greeks developed Philosophy parallel to Mathematics, since the leading philosophers as Thales, Pythagoras, Plato, Aristotle were pioneers in the development of Mathematics and Physics, as a necessary means for revealing the secrets of Nature and the world around us. These philosophers had traveled to Egypt and Babylon and were acquainted with the knowledge of the civilization thereof. They did not confine themselves to obtaining the results, but they searched for proofs and further development of the received ideas and knowledge. Greeks spread from the Italian peninsula to Asia Minor, formulated mathematics as a theoretical d...

Astrolabes in Medieval Cultures, 2019

The plate of eclipses is a special instrument that can be attached onto the astrolabe to produce ... more The plate of eclipses is a special instrument that can be attached onto the astrolabe to produce a rough visualization of the lunar phases, to estimate the time of moon-rising or setting, to find the possibility of a lunar eclipse and to provide information about some relative features, such as the magnitude and the duration of the lunar eclipse.
The instrument described by ʿAlī ibn ʿĪsā comprises a two-sided plate, a grid or rete, an outer limb and an alidade. One side of the plate is for the lunar phases and the time of the moon rising. The other side of the plate is used for the lunar eclipses.
The instrument is reconstracted after merging the two texts describing the instrument and its use. These texts are included in MS Istanbul, Topkapı Saray Kütüphanesi, Ahmet III 3509 ff. 304r–309v (MS T/ ت) and MS Cairo, Dār al-Kutub, Zakī 706, ff. 20r–22r (MS Q/ ق).

Les traités d'Al-Sūfī sur l'astrolabe / Flora Vafea. - Lille : Atelier national de Reproduction des Thèses, 2009. - (Lille-thèses), 2006

Study of the three treatises written by al-Sufi (X century) on the astrolabe (versions T, G, S) u... more Study of the three treatises written by al-Sufi (X century) on the astrolabe (versions T, G, S) using 9 manuscripts. Study of the history of the astrolabe. Introduction to the theory of the stereographic projection for the construction of the astrolabe. Edition of the full Arabic text of chapters XV. 102-106 of G-version, which are concerned with the construction of the northern and southern astrolabe. English translation and commentary on these methods, enriched with additional figures. Full Arabic text and translation into English of S-version, which contains the quintessence of the knowledge on the astrolabe. Analysis of the methods of this version. Detailed comparison of S-version with T and G versions. This comparison leads to interesting conclusions for the evolution of ideas of al-Sufi and his course of research in Astronomy. Appendices: Glossaries of the technical terms and the astrolabe stars, titles of the chapters of T and G versions, correspondence between the chapters o...

Medieval Encounters

The celestial globe is an early astronomical instrument that gives a realistic view of the heaven... more The celestial globe is an early astronomical instrument that gives a realistic view of the heavens and the stars and can simulate the celestial motion, but has some disadvantages such as difficulties in construction, transportation and in carrying out measurements. The astrolabe is an evolution of the celestial globe; it represents the celestial sphere projected onto the plane, retaining the celestial ratios. It provides accurate measurements and helps in solving a great variety of astronomical problems. The aim of this paper is to show how various processes have been transferred from the celestial globe to the astrolabe, determining the form of each part of the astrolabe.

Journal for the History of Astronomy

In their attempt to describe the relative positions of the stars, ancient peoples invented the co... more In their attempt to describe the relative positions of the stars, ancient peoples invented the constellations and created various mythologies. Arabic star mythology is preserved by certain authors, such as al-Ṣūfī and al-Bīrūnī. This paper focuses on a myth of Orion (Jawzā'), Canopus (Suhaīl), Sirius (Yemenite Sirius or al-῾Abūr) and Procyon (Syrian Sirius). According to the myth, the Yemenite and Syrian Sirius were sisters of Suhaīl, both of them situated north of the Galaxy. Suhaīl got married to Jawzā' (Orion), but he fell on her and broke her vertebrae and back. He was afraid that he would be accountable for harming Jawzā', so he escaped to the south, so as not to be visible in the sky. The Yemenite Sirius crossed the Galaxy so as to be with him, and therefore is called al-῾Abūr, the one that traversed, while the Syrian Sirius remained on the north side of the Galaxy, crying for Suhaīl, until her eyes became bleary, and therefore is called al-Ghumaīṣā' (the bleary). The important element of that myth is the movement of the stars portrayed in it. Using the value of the proper motion of Sirius and the astronomical software Voyager, it can be confirmed that Sirius was north of the Milky Way galaxy 42000 years ago, having a galactic latitude of +1;36°, while it is now situated south of the galaxy, having a galactic latitude-8;53,39°. Due to the rotation of the axis of Earth, the declination of Canopus was decreasing approximately between 49850 and 36360 BC, also between 24170 and 12080 BC; this fact can confirm that Canopus moved to the south and became invisible.

Suhayl. International Journal for the History of the Exact and Natural Sciences in Islamic Civilisation, 2017, 2017

This paper focuses on an extract from the treatise of al-Bīrūnī (973-1048 AD) "Comprehension of t... more This paper focuses on an extract from the treatise of al-Bīrūnī (973-1048 AD) "Comprehension of the possible ways for the construction of the astrolabe", where “the plate of the eclipses” is described. This is a device that can be attached on the back side of the astrolabe. It consists of a plate, engraved on both sides, and a grid that can be attached to either side of the plate and can rotate upon it. Given the date of the lunar month, one can find the time of the moon rising and the phase of the moon, using the front side of the plate. Knowing the latitude of the moon at the opposition, one can determine whether there will be a lunar eclipse or not, using the back side of the plate, and can also estimate the magnitude, start time and duration of the eclipse. The results are approximate.