| From: Thomas Hockey et al. (eds.). The Biographical Encyclopedia of Astronomers, Springer Reference. New York: Springer, 2007, pp. 552-553 |
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Ibn Bāṣo: Abū
ʿAlī al‐Ḥusayn ibn Abī Jaʿfar Aḥmad
ibn Yūsuf ibn Bāṣo
Emilia Calvo
Ibn
Bāṣo was the head of the timekeepers
(raʾīs al‐muwaqqitīn) in the Great Mosque of Granada.
He was also a master of the science of calculation, highly skilled in astronomical
observation, an inventor, and the author of several treatises.
Little
is known about Ibn Bāṣo's life. He was probably one of the two Ibn Bāṣos mentioned by Ibn al‐Khaṭīb
in his biographical work, al‐Iḥāṭa, although this author gives his name as Abū ʿAlī
Ḥasan ibn Muḥammad ibn Bāṣo.
According
to Ibn al‐Khaṭīb, Ibn Bāṣo
was from the Sharq al‐Andalus, the eastern part of the Iberian
Peninsula. The fact that he was the head of the timekeepers (raʾīs
al‐muwaqqitīn) in the Great Mosque of Granada is extremely
interesting, because it suggests that the mosque had an organized, institutionalized
group devoted to timekeeping.
Two of
Ibn Bāṣo's written texts are preserved. One of them is the Risālat
al‐ṣafīḥa
al‐jāmiʿa
li‐jamīʿ al‐ʿurūḍ
(Treatise on the universal plate for all latitudes). The other is the Risālat
al‐ṣafīḥa
al‐mujayyaba dhāt al‐awtār (Treatise on the plate of sines provided with chords).
In both texts the author is named as Abū ʿAlī al‐Ḥusayn ibn Abī Jaʿfar
Aḥmad ibn Yūsuf
ibn Bāṣo and is described as amīn awqāt al‐ṣalawāt (keeper of the times
of prayers) and imām al‐muʾadhdhinīn (leader of
the muezzins).
The
differences in name between what one finds in Ibn al‐Khaṭīb's
biography and in the treatises themselves have led some specialists (such
as George Sarton) to suggest that there were two Ibn Bāṣos. However, later investigators—H. P. J. Renaud, among
others—proposed that the treatises were the work of one and the same person,
adducing that differences in the name were frequent in Arabic biographies.
The first
treatise, the Risālat al‐ṣafīḥa
al‐jāmiʿa
li‐jamīʿ al‐ʿurūḍ,
was compiled in the year 1273 and was devoted to the description of the use
of a universal plate for all latitudes. The author states that he was the
inventor of the instrument. The treatise suggests that the author was aware
of the work of previous astronomers in the Muslim world, especially of the
work carried out in the 11th century in Andalusia. There are also similarities
with some treatises of mīqāt written in 13th‐century
Egypt. The astrolabe plate is one in which the horizontal coordinates have
been omitted, and the horizons have been multiplied in order to serve for
different latitudes. It corresponds to the type of instrument usually called
ṣafīḥa
āfāqiyya, “plate of horizons,”
and it is similar to a conventional astrolabe plate. The fact that this plate
does not have horizontal coordinates and is limited to the projection of a
set of horizons has led specialists to think that it was used only for simple
operations. However, a study of the treatise shows that the instrument was
as versatile as any other astrolabe plate, although it is difficult to use
because of the number of lines in its layout and because of the complicated
procedures that the user would need to know. In this treatise the author is
not seeking great precision: the values are clearly rounded. It was probably
the didactic potential of the plate that the author was most interested in
exploiting. Indeed, using the plate would have provided a very useful exercise
for anybody who wanted to become familiar with the celestial spheres and their
properties. This plate seems to have been designed to carry out all types
of speculative calculation: its use in extreme northern latitudes or in latitudes
south of the equator cannot be considered a practical application. Nevertheless,
the possibility of using this plate as a southern astrolabe plate, in spite
of the fact that it is designed for the Northern Hemisphere and is meant to
fit in a northern astrolabe, is its most original characteristic and thus
can be considered a forerunner of later instruments.
Ibn
Bāṣo's work became well known.
There are a number of summaries of the treatise, most of them of Maghribi
origin, and the projection was included in several instruments still preserved
in Andalusia, North Africa, and also in the Islamic East as is the case of
instruments constructed by Mizzī in
Damascus and Allāh‐Dād in Lahore. Although universal instruments
of this type had already been described by earlier astronomers such as Sijzī
or Bīrūnī, they do not
seem to have been built until the time of Ibn Bāṣo, when, starting in the 14th
century, they seem to have proliferated in North Africa and the Muslim East
as well as in Europe.
The other
treatise written by Ibn Bāṣo that is still preserved, the
Risālat al‐ṣafīḥa
al‐mujayyaba dhāt al‐awtār, is contained in manuscript 5550 of the National Library
of Tunisia. The introduction of this treatise presents abundant similarities
to that of the previous one. In this treatise, the author describes the use
of a trigonometric plate of his invention that can perform all kinds of calculations
of spherical astronomy.
Selected References
Brockelmann, Carl
(1937). Geschichte der arabischen Litteratur. Suppl. 1, p. 860.
Leiden: E. J. Brill.
Calvo, Emilia
(1991). “Les échos de l'oeuvre d'Ibn Bāṣo en Afrique du Nord.”
In Le Patrimoine Andalous dans la Culture Arabe et Espagnole, pp. 65–79.
Tunis.
——— (1992). “Ibn Bāṣo's Universal
Plate and Its Influence in European Astronomy.” Scientiarum
historia 18: 61–70.
——— (1992).
“La ciencia en la Granada nazarí (Ciencias exactas y tecnología).” In El
legado científico andalusí, edited by Juan G. Vernet
and Julio Samsó, pp. 117–126. Madrid.
——— (1993). Abū
ʿAlī al‐Ḥusayn
Ibn Bāṣo (m. 716/1316): Risālat
al‐ṣafīḥa al‐jāmiʿa
li‐jamīʿ al‐ʿurūḍ. Edición crítica, traducción y estudio. Madrid.
——— (1994). “On
the Construction of Ibn Bāṣo's
Universal Astrolabe (14th C.) According to a Moroccan Astronomer of
the 18th Century.” Journal for the History of Arabic Science 10: 53–67.
——— (1996). “Ibn Bāṣo's Astrolabe
in the Maghrib and East.” In From Baghdad
to Barcelona: Studies in the Islamic Exact Sciences in Honour of Prof. Juan
Vernet, edited by Joseph Casulleras
and Julio Samsó, vol. 2, pp. 755–767. Barcelona: Instituto “Millás Vallicrosa” de Historia
de la Ciencia árabe.
——— (2000). “A
Study of the Use of Ibn Bāṣo's
Universal Astrolabe Plate.” Archives internationales d'histoire
des sciences 50: 264–295.
——— (2001). “Transformation
of Coordinates in Ibn Bāṣo's
al‐Risāla fī
ʾl‐ṣafīḥa al‐mujayyaba dhāt al‐awtār.” Journal for the History of Arabic
Science 12: 3–21.
Ibn
al‐Khatīb, Lisān
al‐Dīn (1973). al‐Iḥāṭa
fī akhbār Gharnāta, edited by Muḥammad
ʿAbd Allāh ʿInān. Vol.
1, p. 468. Cairo.
Renaud, H.
P. J. (1932). “Additions et Corrections à Suter.” Isis 18:
166–183, n. 381b.
——— (1937).
“Notes critiques d'histoire des sciences chez les musulmans. I. Les
Ibn Bāṣo.”
Hesperis 24: 1–12.
——— (1942).
“Quelques constructeurs d'astrolabes en occident musulman.” Isis 34:
20–23.
Samsó, Julio
(1966). “Nota acerca de cinco manuscritos sobre astrolabio.” Al‐Andalus 31: 385–392.
——— (1973).
“À propos de quelques manuscrits astronomiques des bibliothèques de Tunis:
Contribution à une étude de l'astrolabe dans l'Espagne musulmane.” In Actas del II Coloquio
Hispano‐Tunecino, pp. 171–190. Madrid.
Sarton, George
(1947). Introduction to the History of Science. Vol. 3, pt. 1, p. 696.
Baltimore: Published for the Carnegie Institution of Washington by Williams
and Wilkins.
Suter, Heinrich
(1900). “Die Mathematiker und Astronomen der Araber und ihre Werke.” Abhandlungen
zur Geschichte der mathematischen
Wissenschaften 10: 157, n. 381b.