as-Sidschzī

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A page from As-Siǧzî's geometrical treatise
Model of the solar system and the movement of the earth ( planetarium ) according to as-Siǧzî

Abū Saʿīd Ahmad ibn Muhammad as-Sidschzī ( Arabic أبو سعید أحمد بن محمد السجزي, DMG Abū Saʿīd Aḥmad ibn Muḥammad as-Siǧzī ; born around 945; died around 1020), also known as al- Sinjari and Sidschzi (as well as Alsidschzi and al-Sidschzi ; English transcribed al-Sijzi or as-Sijzi , is the short form of "as-Sidschistani"), was an Iranian astronomer , mathematician and astrologer . He was in close corresponding contact with al-Biruni . He also suspected that the earth rotates around an axis .

Life

The traditions of As-Siǧzî's life are only available in fragments. It is only certain that his father Abu 'l-Husayn Muhammad ibn' Abdalalgalil was a geodesic and that, as the name Siǧzî suggests, he was born in Sègistan, today's Sistan . It is assumed that his most productive creative period was between the years 960 and 1,000. In addition, there was probably a certain dependence on his patron Adud ad-Daula , a potentate in Balch , to whom he dedicated several of his writings. His participation in the astronomical observations in Shiraz during the winter solstice in 969 and 970 is certain .

Act

As-Siǧzî's love of experimentation made him vary a common astrolabe . In one of his variants, for example, he swapped the rete and the mater for the common instruments, with which his colleague al-Biruni tried to prove the thesis that the earth rotates and the sky is immobile.

When As-Siǧzî with conic sections concerned, he found an easier way to an angle tripartite division to determine: he replaced the out of the ancient native kinematic tripartite division by a purely geometric solution from the intersection of a circle with an equilateral hyperbola results.

The construction of a small planetarium , which was conceived as a model of the Ptolemaic worldview , also goes to the account of As-Siǧzîs . The sun and the planets rotate around the earth inside a spherical grid on which even cities, mountains, seas and deserts have been engraved. A replica can be seen in the museum of the Institute for the History of Arab-Islamic Sciences at the Goethe University in Frankfurt am Main .

To the present day there are still more than 40 treatises on elementary geometry and conic sections, which As-Siǧzî wrote in the tradition of ancient Greece, but which have not yet been translated into any Western language. Most of these works are the basics of the subject and are primarily intended for beginners in this subject. However, later generations of mathematics found numerous errors in his somewhat more demanding textbooks.

Web links

literature

proof

  1. ↑ a b Model of the solar system and the movement of the earth ("planetarium") according to as-Siǧzî. Museum of the Institute for the History of Arab-Islamic Sciences, 2010, accessed on March 26, 2020 .
  2. ↑ Alessandro Bausani: Cosmology and Religion in Islam . In: Scientia / Rivista di Scienza . 108, No. 67, 1973, p. 762.
  3. ↑ MJL Young (Ed.): Religion, Learning and Science in the 'Abbasid Period . Cambridge University Press , November 2, 2006, ISBN 978-0-521-02887-5 , p.  413 .
  4. ^ JJ O'Connor, EF Robertson: Abu Said Ahmad ibn Muhammad Al-Sijzi. MacTutor History of Mathematics archive, 1999, accessed March 26, 2020 .
  5. ^ Jan P. Hogendijk : Al-Sijzi's Treatise on Geometrical Problem Solving. (PDF) 1996, p. VIII , accessed on March 26, 2020 (English).
  6. ^ A b Jan P. Hogendijk: al-Sigzi, Abu Sacid Ahmad ibn Muhammad ibn 'Abdalgalli , Lexicon of Eminent Natural Scientists, 2007, Volume 3; Elsevier GmbH, Munich; P. 295; ISBN 3-8274-1883-6
personal data
SURNAME As-Siǧzî
ALTERNATIVE NAMES Abu Sa'id Ahmed ibn Mohammed ibn Abd al-Jalil al-Sijzi; Sinjari, al-; Sijazi, al-
BRIEF DESCRIPTION Persian astronomer, mathematician and astrologer
DATE OF BIRTH at 945
DATE OF DEATH around 1020