From: Thomas Hockey et al. (eds.). The Biographical Encyclopedia of Astronomers, Springer Reference. New York: Springer, 2007, pp. 570-572

Courtesy of

Ibn Sīnā: Abū ʿAlī al‐usayn ibn ʿAbdallāh ibn Sīnā

Sally P. Ragep

Alternate names


BornAfshana (near Bukhārā, Uzbekistan), 980

DiedHamadhān (Iran), 1037

Ibn Sīnā, also known as Avicenna, is renowned for his great works in philosophy and medicine. He was also interested in the mathematical sciences, and he dealt with a number of problems related to astronomy and cosmology that had an impact on later astronomical work in Islamic regions and in Europe.

Ibn Sīnā lived a full and colorful life and left an autobiography that was completed by his associate Abū ʿUbayd al-Jūzjānī. Here we emphasize his astronomical career. Ibn Sīnā lived in Bukhārā between 985 and 1005 where he studied Ptolemy's Almagest at an early age, basically being self‐taught. It is said that he had access to the library of Nū ibn Manūr (died: 997), which included many books by the “Ancients.” Ibn Sīnā lived in Gurganj from 1005 to 1012 where he wrote Station of the Earth. He then resided in Jurjān (1012–1014), and during that brief period he wrote his Comprehensive Observations, a treatise on the Correction of the Longitude of Jurjān, and his Summary of the Almagest (which he probably later incorporated into al‐Shifāʾ, his great philosophical encyclopedic work). It was here that Jūzjānī began studying the Almagest with him. In 1014–1015, Ibn Sīnā moved to Rayy and then on to Hamadhān (1015–1024), where he wrote several parts of the Shifāʾ. He lived his final years in Ifahān, where he completed the final parts of the Shifāʾ, including the Almagest, composed the Najāt (the abridgement of the Shifāʾ that included logic, natural philosophy, and theology), and wrote his treatise on Astronomical Instruments during periods of observation for the ruler ʿAlā' al‐Dawla. After Ibn Sīnā's death, Jūzjānī added supplemental treatises on astronomy and mathematics to his Najāt.

There are many astronomical works associated with Ibn Sīnā, but nine can be identified as authentic, and these can be classified into four general categories: summaries of Ptolemy's Almagest, works on instruments and observational astronomy, philosophical and cosmological works, and miscellaneous works.


Ibn Sīnā's Tarīr al‐majisī is an extensive summary of the Almagest. Composed in Jurjān between 1012 and 1014, he later revised it, and it became Part 4 of the mathematical section of the Shifāʾ. Two works of Ibn Sīnā that are often treated as separate treatises but are really part of the above work are:


his Ibtidāʾ al‐maqāla al‐muāfa ilā mā ikhtaara min kitāb al‐majisī mimmā laysa yadullu ʿalayhī al‐majisī (Beginning of the treatise appended to the summary of the Almagest containing what is not indicated in the Almagest). Ibn Sīnā states: “it is incumbent upon us to bring that which is stated in the Almagest and what is understood from Natural Science into conformity.” Among the topics included are the dynamics of celestial motion, a mathematical examination of the implications of the theoretical construction of Ibrāhīm ibn Sinān (who is unnamed) that would account for the discrepancies between Ptolemy's precessional rate and his obliquity, and those of 9th‐century Islamic astronomers (Ibn Sīnā gives his own observed value of the obliquity as 23;33,30°); the motion of the solar apogee, taken to be fixed by Ptolemy, and a proposal to explain its motion; and, the problem of latitude brought about by the epicycle poles.


his Fī an laysa li‐ʾl‐ar arakat intiqāl (That the Earth does not have local motion), where Ibn Sīnā gives an account of Ptolemy's arguments against the possibility of the Earth's rotation but indicates that they are inadequate.


Ibn Sīnā's al‐Arād al‐kulliyya (Comprehensive observations) was written in Jurjān (between 1012 and 1014) for Abū Muammad al‐Shīrāzī and incorporated by Jūzjānī into Ibn Sīnā's Najāt after his death. This short work contains nine chapters and was translated into Persian as Raadhā kullī in the Dānishnāmah‐i ʿilāʾī. Ibn Sīnā states that he wishes to “abridge the explication of the comprehensive observations from which one learns the general principles regarding the configuration of the orb and the calculation of the motions.”


Ibn Sīna wrote Maqāla fī al‐ālāt al‐raadiyya (Treatise on astronomical instruments) in Ifahān sometime between 1024 and 1037, during his period of observations for ʿAlā' al‐Dawla. This work indicates a practical side to Ibn Sīnā's astronomical interests and also demonstrates his interest in precision.


ūl Jurjān ([Correction of the] longitude of Jurjān) was written in Jurjān (1012–1014) and dedicated to Zarrayn Kīs, daughter of Amīr Qābūs (= Shams al‐Maʿālī). It is not extant but is discussed by Bīrūnī in his Tadīd al‐amākin, disparaging Ibn Sīnā's abilities in practical astronomy.


al‐Samāʾ wa‐ʾl‐ʿālam (De caelo et mundo) was written for Abū al‐usayn Amad al‐Sahlī [Suhaylī?]. Most likely, this is what later became the chapter of the same name in the Shifāʾ.


Maqāla fī al‐ajrām al‐samāwiyya (al‐ʿulwiyya) (Treatise on the celestial bodies). Like (5), this work is written from the perspective of cosmology/natural philosophy, not mathematical astronomy.


ʿIllat qiyām al‐arayyizihā (fī wasa al‐samāʾ) (On the cause of the Earth's remaining in its position [in the middle of the heavens] = Station of the Earth). It was written in Gurganj (circa 1005–1012), and dedicated to al‐Sahlī to whom al‐Samāʾ wa‐ʾl‐ʿālam is also dedicated.


Maqāla (Risāla) fī ibāl ʿilm (akām) al‐nujūm (Essay on the refutation of astrology) or Risāla fī al‐radd ʿalā al‐munajjimīn (Treatise replying to the astrologers). This treatise attacks astrology and, along with his work on the categorization of the sciences, demonstrates Ibn Sīnā's attempt to demarcate astronomy from astrology.


Maqāla fī khawāṣṣ khaṭṭ al‐istiwāʾ (Essay on the characteristics of the Equator). This work is no longer extant but Ibn Sīnā's position that the equatorial region is the most temperate is known from his Canon on Medicine and from his critics, which included Bīrūnī, Fakhr al‐Dīn al‐Rāzī, and Naīr al‐Dīn al‐ūsī.

Some of the works associated with Ibn Sīnā are misattributions, uncertain works, or duplications (due to longer or slightly different titles). (For details, see Ragep and Ragep.)

Ibn Sīnā's astronomical knowledge and works may be viewed as less developed than those of his contemporaries such as Ibn al‐Haytham and Bīrūnī; nevertheless, he had an impact upon later writers, and several general points can be made about his astronomical work.

First, Ibn Sīnā shows a remarkable interest in observational astronomy. Later writers refer to his observation of a Venus transit of the Sun, when it was seen as a mark on its face. This helped him establish that Venus was, at least sometimes, below the Sun. He also gave a new obliquity observation of 23;33,30° and provided a new longitude distance for Jurjān, from Baghdad, of 9;20° (compared with the traditional value of 8;0° and the modern value of 10;3°). Ibn Sīnā's treatise on instruments includes a description of a large instrument with an improved sighting system that theoretically could provide considerably improved accuracy. Also, his summaries tend to emphasize the role of observation. Noteworthy as well are Ibn Sīnā's criticisms of the poor instruments and observations of Ptolemy and Hipparchus.

Second, Ibn Sīnā's cosmological writings are more within the tradition of natural philosophy rather than mathematical astronomy, and there is no extant work (and none reported) that one could call a hayʾa work (i.e., one that provided a physical account of the mathematical models of the Almagest). One can therefore understand his concern with the dynamics of celestial motion and his reliance on natural philosophy to criticize Ptolemy's attempt to rely strictly upon empirical evidence to disprove the possible rotation of the Earth. He is also aware of violations of the accepted physics in Ptolemy's models as well as the need for reforming the Ptolemaic system and reconciling physics with mathematical astronomy.

Finally, Ibn Sīnā plays a significant role in redefining and recategorizing astronomy. He demarcates exact mathematical astronomy (ʿilm al‐hayʾa) from astrology, which he views as being part of natural philosophy.

Selected References

Dānish‐pazhūh, Muammad Taqī (1985). Al‐Najāt min al‐gharq baḥr al‐dalālāt. Tehran: Dānešgāh‐e Tehrān.

Gohlman, William E. (1974). The Life of Ibn Sīnā: A Critical Edition and Annotated Translation. Albany: State University of New York Press.

Ibn Sīnā, Abū ʿAlī al‐usayn ibn ʿAbdallāh (1969). Al‐Shifāʾ. Al‐Samāʾ wa‐ʾl‐ʿālam (Part 2 of Natural Philosophy), edited by Maḥmūd Qāsim. Cairo.

——— (1980). Al‐Shifāʾ. ʿIlm al‐hayʾa (Part 4 of Mathematics [al‐Riyāḍiyyāt]), edited by Muammad Madwar and Imām Ibrāhīm Aḥmad. Cairo.

Mehren, A. F. Von. (1884). “Vues d'Avicenne sur l'astrologie et sur le rapport de la responsabilité humaine avec le destin.” Muséon 3: 382–403.

Ragep, F. Jamil and Sally P. Ragep (2004). “The Astronomical and Cosmological Works of Ibn Sīnā: Some Preliminary Remarks.” In Sciences, techniques et instruments dans le monde iranien (Xe– XIXe siècle), edited by N. Pourjavady and Ž. Vesel, pp. 3–15. Actes du colloque tenu à l'Université de Téhéran (7–9 juin 1998). Tehran.

Renaud, Michel (1973). “Le ‘De celo et mundo’ d'Avicenne.” Bulletin de philosophie médiévale 15: 92–130.

Saliba, George (1980). “Ibn Sīnā and Abū ʿUbayd al‐Jūzjānī: The Problem of the Ptolemaic Equant.” Journal for the History of Arabic Science 4: 376–403. (Reprinted in Saliba, A History of Arabic Astronomy. New York: New York University Press, 1994, pp. 85–112.)

Wiedemann, Eilhard (1925). “Über ein von Ibn Sînâ (Avicenna) hergestelltes Beobachtungsinstrument.” Zeitschrift für Instrumentenkunde 45: 269–275. (Reprinted in Wiedemann, Gesammelte Schriften zur arabisch‐islamischen Wissenschaftsgeschichte. Frankfurt am Main, 1984, Vol. 2, pp. 1110–1116.)

Wiedemann, Eilhard and Th. W. Juynboll (1927).Avicennas Schrift über ein von ihm ersonnenes Beobachtungsinstrument.” Acta orientalia 11, no. 5: 81–167. (Reprinted in Wiedemann, Gesammelte Schriften zur arabisch‐islamischen Wissenschaftsgeschichte. Frankfurt am Main, 1984, Vol. 2, pp. 1117–1203.)