ابن سهل

نسخة من صفحة بمخطوط ابن سهل تظهر اكتشافه لقانون الانكسار (من راشد، 1990). يُظهر الجزء السفلي من الشكل تمثيلًا لعدسة محدبة مستوية (على اليمين) ومحورها الرئيسي (الخط الأفقي المتقاطع). يؤدي انحناء الجزء المحدب من العدسة إلى توجيه جميع الأشعة الموازية للمحور الأفقي (والتي تقترب من العدسة من اليمين) إلى نقطة بؤرية على المحور على اليسار.

شرح لنظام بن سهل. إذا ظلت النسبة بين طولين

L_{1}/L_{2}

تساوي

n_{1}/n_{2}

فإن الأشعة تتبع قانون الجيوب، أو قانون سنل. يُظهِر الوتر الداخلي للمثلث قائم الزاوية مسار شعاع (بصريات)الشعاع الساقط ويُظهِر الوتر الخارجي امتدادًا لمسار الشعاع المنكسر. إذا التقى الشعاع الساقط بتغير في الوسط يكون وجهه عموديًا عند نقطة تقاطع الوترين. نسبة طول الوتر الأصغر إلى الأكبر هي نسبة معاملات الانكسار للوسطين.^[1]

أبو سعد العلاء ابن سهل، وشهرته ابن سهل (و. ح. 940 - ت. 1000)، هو رياضياتي وفيزيائي فارسي^[2]^[3]^[4]^[5] من العصر الذهبي الإسلامي^[6] ارتبط اسمه بالبلاط البويهي في بغداد. ولا شيء في اسمه يدل على موطنه الأصلي.^[7]

ومن المعروف أنه كتب رسالة بصرية حوالي عام 984. وقد أعاد رشدي راشد بناء نص هذه الرسالة من مخطوطتين حُررتا عام 1993 هما: مخطوطة دمشق (MS 4871, 3 fols) ومخطوطة طهران (Millī MS 867, 51 fols)، وعلى الرغم من أن مخطوطة طهران أطول بكثير، إلا أنها تعرضت لأضرار بالغة، في حين تحتوي مخطوطة دمشق على قسم مفقود تمامًا من مخطوطة طهران. تحمل مخطوطة دمشق اسم في الأعلى المحرقة ("في آلات الإحراق")، بينما أضيف لمخطوطة طهران اسم في كتاب لاحق بعنوان كتاب الحراقات ("كتاب المواقد").

ابن سهل هو أول عالم مسلم عُرف بدراسة كتاب البصريات لپطليموس، وبالتالي فهو يعتبر مقدمة هامة لكتاب البصريات لابن الهيثم، الذي كتب بعد حوالي ثلاثين عاماً.^[8] تناول ابن سهل الخواص البصرية للمرايا المنحنية والعدسات ووصف بأنه مكتشف قانون الانكسار (قانون سنل).^[9]^[10]^[11] استخدم ابن سهل هذا القانون لاستنتاج أشكال العدسات التي تركز الضوء بدون انحرافات هندسية، والمعروفة باسم العدسات الشبه كروية. وفي بقية الرسالة تحدث ابن سهل عن المرايا المكافئة، والمرايا الإهليلجية، والعدسات المحدبة، وتقنيات رسم الأقواس الزائدية.

قام ابن سهل بتصميم عدسات محدبة تعمل على تجميع أشعة الضوء المتوازية، مما قد يؤدي إلى حرق الجسم على مسافة محددة.^{[بحاجة لمصدر]}

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انظر أيضاً

المصادر

^ Kurt Bernardo Wolf, Geometric Optics on Phase Space, p. 9, Springer, 2004, ISBN 3-540-22039-9 online
^ Enterprise of Science in Islam: New Perspectives - J. P. Hogendijk, A. I. Sabra "The first clear evidence we have of a correct understanding of Ptolemy's theory of refraction does not appear in the Arabic sources available to us until the second half of the tenth century, when the Persian mathematician al-Ala ibn Sahl was able to put Ptolemy's ideas to use in formulating entirely original geometrical arguments for the construction of burning instruments by means of refraction"
^ http://www.iranicaonline.org/articles/optics,"There are a number of optical texts by authors with a Persian ethnicity or association. The earliest is Abu Saʿd al-ʿAlāʾ Ebn Sahl at the Persian Buyid court (945–1055), better known for his early conception of the “sine law of refraction” and burning mirrors (Rashed, 1990, pp. 464-68; 1993; 2005) than his work on optics proper (Sabra, 1989, pp. lix-lx; 1994)."
^ https://ijhpm.org/index.php/IJHPM/article/download/111/62,"Exploiting^{[dead link]} the 10th-century Persian mathematician Ibn Sahl’s development on Ptolemy’s studies of refraction,48 he generalized the relationship between incident and refracted rays in a form that presaged Snell’s law."
^ https://www.sciencelearn.org.nz/resources/1867-light-ideas-and-technology-timeline,"Persian scientist Ibn Sahl writes On burning mirrors and lenses, which sets out his understanding of how curved mirrors and lenses bend and focus light. He discovers a law of refraction mathematically equivalent to Snell’s law (1615)."
^ Hogendijk, edited by Jan P.; Sabra, Abdelhamid I. (2003). The enterprise of science in Islam : new perspectives. Cambridge, Mass.; London: MIT. p. 89. ISBN 0-262-19482-1. {{cite book}}: |first1= has generic name (help)
^ "Nothing in his surname and given names, however, allows us to glimpse either his country of origin or his social and religious allegiance — unless a link may be established with another Ibn Sahl of the same period, who was an astrologer concerned with mathematics; for the time being, however, this connection has no historical value." Roshdi Rashed, Geometry and Dioptrics in Classical Islam, London (2005), p. 3.
^ Rashed (1990:"Ibn al-Haytham was not the first to have effectively used Ptolemy's Optics, [...] al-Kindi was not the only significant figure in the history of Arabic optics before Ibn al-Haytham"
^ "Roshdi Rashed, Historian of Greek and Arabic Mathematics". 2017: 12. {{cite journal}}: Cite journal requires |journal= (help)
^ http://spie.org/etop/2007/etop07fundamentalsII.pdf," R. Rashed credited Ibn Sahl with discovering the law of refraction [23], usually called Snell’s law and also Snell and Descartes’ law."
^ Smith, A. Mark (2015). From Sight to Light: The Passage from Ancient to Modern Optics (in الإنجليزية). University of Chicago Press. p. 178. ISBN 9780226174761.

المراجع

Rashed, R. "A pioneer in anaclastics: Ibn Sahl on burning mirrors and lenses", Isis 81, pp. 464–491, 1990.
Rashed, R., Géométrie et dioptrique au Xe siècle: Ibn Sahl, al-Quhi et Ibn al-Haytham. Paris: Les Belles Lettres, 1993
Zghal, Mourad; et al. (2007). Nantel, Marc (ed.). "The first steps for learning optics: Ibn Sahl's, Al- Haytham's and Young's works on refraction as typical examples" (PDF). The Education and Training in Optics and Photonics Conference. Tenth International Topical Meeting on Education and Training in Optics and Photonics. International Commission for Optics. 9665: 3. Bibcode:2007SPIE.9665E..09Z. doi:10.1117/12.2207465. S2CID 13875045. Retrieved 20 June 2011.
Berggren, Len (2007). "Ibn Sahl: Abū Saʿd al-ʿAlāʾ ibn Sahl". In Thomas Hockey; et al. (eds.). The Biographical Encyclopedia of Astronomers. New York: Springer. p. 567. ISBN 978-0-387-31022-0. (PDF version)
Selin, Helaine (1997). Encyclopaedia of the History of Science, Technology, and Medicine in Non-Western Cultures. Springer Science & Business Media. pp. 432–433. ISBN 978-07-92-34066-9.
Sarmiş, İbrahım (1999). İBN SEHL - An article published in Turkish Encyclopedia of Islam. Vol. 20. Istanbul: TDV İslâm Ansiklopedisi. p. 312. ISBN 978-97-53-89447-0.

[1] Kurt Bernardo Wolf, Geometric Optics on Phase Space, p. 9, Springer, 2004, ISBN 3-540-22039-9 online

[2] Enterprise of Science in Islam: New Perspectives - J. P. Hogendijk, A. I. Sabra "The first clear evidence we have of a correct understanding of Ptolemy's theory of refraction does not appear in the Arabic sources available to us until the second half of the tenth century, when the Persian mathematician al-Ala ibn Sahl was able to put Ptolemy's ideas to use in formulating entirely original geometrical arguments for the construction of burning instruments by means of refraction"

[3] ttp://www.iranicaonline.org/articles/optics,"There are a number of optical texts by authors with a Persian ethnicity or association. The earliest is Abu Saʿd al-ʿAlāʾ Ebn Sahl at the Persian Buyid court (945–1055), better known for his early conception of the “sine law of refraction” and burning mirrors (Rashed, 1990, pp. 464-68; 1993; 2005) than his work on optics proper (Sabra, 1989, pp. lix-lx; 1994)."

[4] ttps://ijhpm.org/index.php/IJHPM/article/download/111/62,"Exploiting^{[dead link]} the 10th-century Persian mathematician Ibn Sahl’s development on Ptolemy’s studies of refraction,48 he generalized the relationship between incident and refracted rays in a form that presaged Snell’s law."

[5] ttps://www.sciencelearn.org.nz/resources/1867-light-ideas-and-technology-timeline,"Persian scientist Ibn Sahl writes On burning mirrors and lenses, which sets out his understanding of how curved mirrors and lenses bend and focus light. He discovers a law of refraction mathematically equivalent to Snell’s law (1615)."

[6] Hogendijk, edited by Jan P.; Sabra, Abdelhamid I. (2003). The enterprise of science in Islam : new perspectives. Cambridge, Mass.; London: MIT. p. 89. ISBN 0-262-19482-1. {{cite book}}: |first1= has generic name (help)

[7] "Nothing in his surname and given names, however, allows us to glimpse either his country of origin or his social and religious allegiance — unless a link may be established with another Ibn Sahl of the same period, who was an astrologer concerned with mathematics; for the time being, however, this connection has no historical value." Roshdi Rashed, Geometry and Dioptrics in Classical Islam, London (2005), p. 3.

[8] Rashed (1990:"Ibn al-Haytham was not the first to have effectively used Ptolemy's Optics, [...] al-Kindi was not the only significant figure in the history of Arabic optics before Ibn al-Haytham"

[9] "Roshdi Rashed, Historian of Greek and Arabic Mathematics". 2017: 12. {{cite journal}}: Cite journal requires |journal= (help)

[10] ttp://spie.org/etop/2007/etop07fundamentalsII.pdf," R. Rashed credited Ibn Sahl with discovering the law of refraction [23], usually called Snell’s law and also Snell and Descartes’ law."

[11] Smith, A. Mark (2015). From Sight to Light: The Passage from Ancient to Modern Optics (in الإنجليزية). University of Chicago Press. p. 178. ISBN 9780226174761.

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