Ibnu Sahal (matematikawan)

Abu Saad al-Ala Ibnu Sahal (bahasa Arab: أبو سعد العلاء ابن سهل; hidup k. 940–1000), lebih dikenal hanya sebagai Ibnu Sahal, adalah matematikawan dan fisikawan berkebangsaan Persia^[1]^[2]^[3]^[4] pada Zaman Kejayaan Islam,^[5] yang berafiliasi dengan istana Buwaihi di Bagdad. Tidak ada dalam namanya yang memungkinkan kampung halaman atau tempat kelahirannya, tidak seperti nama-nama Islam dan Timur Tengah pada umumnya.^[6]

Dia diketahui telah menulis risalah optik pada sekitar tahun 984. Risalah itu direkonstruksi oleh Roshdi Rashed dari dua naskah (disunting pada tahun 1993).: Damaskus, al-Ẓāhirīya MS 4871, 3 fols., dan Teheran, Millī MS 867, 51 fols. Naskah Teheran jauh lebih panjang, tetapi rusak parah, dan naskah Damaskus berisi bagian yang telah hilang seluruhnya dalam naskah Teheran. Naskah Damaskus berjudul Fī al-'āla al-muḥriqa ("Pada perkakas yang terbakar"), naskah Teheran memiliki judul yang ditambahkan di kemudian hari berjudul Kitāb al-harrāqāt ("Kitab pembakar").

Ibnu Sahal adalah cendekiawan Muslim pertama yang diketahui telah mempelajari catatan Ptolemaios berjudul Optik, dan sebagai sumber penting untuk Kitab Optik yang ditulis oleh Ibnu al-Haitsam (Alhazen), yang ditulis sekitar tiga puluh tahun kemudian.^[7] Ibnu Sahl berurusan dengan sifat optik cermin dan lensa tidak datar dan dia disebut sebagai penemu hukum pembiasan (hukum Snellius).^[8]^[9] Ibnu Sahal menggunakan hukum ini untuk mendapatkan bentuk lensa yang memfokuskan cahaya tanpa penyimpangan geometris, yang dikenal sebagai lensa anaklastik. Di bagian risalah yang tersisa, Ibnu Sahal membahas cermin parabola, cermin elips, lensa bikonveks, dan teknik menggambar busur hiperbola.

Ibnu Sahal merancang lensa cembung yang memfokuskan sinar cahaya yang sejajar, yang dapat menyebabkan suatu benda terbakar pada jarak tertentu. Sebuah bikonveks memiliki kemampuan untuk fokus pada titik tertentu pada jarak yang tak terbatas. Ibnu sahl telah membuat banyak kontribusi untuk Optik, ia juga menulis artikel tentang bola langit. Rasio konstan adalah titik fokus utama penelitiannya, dan memungkinkan pemahaman yang lebih baik tentang lensa refraksi. Ibnu Sahl melakukan eksperimen di mana sepotong kristal digunakan untuk menyebarkan sinar cahaya melalui kristal yang kemudian dibiaskan di udara.

Referensi

Catatan kaki

^ 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^{[pranala nonaktif permanen]} 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. hlm. 89. ISBN 0-262-19482-1.
^ "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"
^ 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 (dalam bahasa Inggris). University of Chicago Press. hlm. 178. ISBN 9780226174761.

Daftar pustaka

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 . Diakses tanggal 20 June 2011.
Berggren, Len (2007). "Ibn Sahl: Abū Saʿd al‐ʿAlāʾ ibn Sahl". Dalam Thomas Hockey; et al. The Biographical Encyclopedia of Astronomers. New York: Springer. hlm. 567. ISBN 978-0-387-31022-0. (PDF version)
Selin, Helaine (1997). Encyclopaedia of the History of Science, Technology, and Medicine in Non-Westen Cultures. Springer Science & Business Media. hlm. 432–433. ISBN 978-07-92-34066-9.
Sarmiş, İbrahım (1999). İBN SEHL - An article published in Turkish Encyclopedia of Islam. 20. Istanbul: TDV İslâm Ansiklopedisi. hlm. 312. ISBN 978-97-53-89447-0.

[1] 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"

[2] 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)."

[3] ttps://ijhpm.org/index.php/IJHPM/article/download/111/62,"Exploiting^{[pranala nonaktif permanen]} 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."

[4] 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)."

[5] Hogendijk, edited by Jan P.; Sabra, Abdelhamid I. (2003). The enterprise of science in Islam : new perspectives. Cambridge, Mass. ; London: MIT. hlm. 89. ISBN 0-262-19482-1.

[6] "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.

[7] 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"

[8] 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."

[9] Smith, A. Mark (2015). From Sight to Light: The Passage from Ancient to Modern Optics (dalam bahasa Inggris). University of Chicago Press. hlm. 178. ISBN 9780226174761.

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