This article aims to test a new method of dating optico-astronomical manuscripts, using Ibn al-Haytham’s Epistle on the Shape of the Eclipse as the test case. This work is selected because of indications that its diagrams are based on reality. After clarifying the observation conditions, an astronomical ephemeris is applied to sift through the eclipses that occurred during Ibn al-Haytham’s life throughout the area he is believed to have sojourned. Next, the remaining eclipses are sorted by computing the image projection. The results show that Ibn al-Haytham’s Epistle is likely to have reported the partial solar eclipse of 28 Rajab AH380/21 October 990 in Baṣra. Because this exercise is primarily the test of a new method, this finding should be regarded as a tentative outcome, pending further information.
John M. Steele, “A Re-Analysis of the Eclipse Observations in Ptolemy’s Almagest,”Centaurus, 2000, 42:89–108. F. Richard Stephenson, John M. Steele, “Astronomical Dating of Babylonian Texts Describing the Total Solar Eclipse of S.E. 175,” Journal for the History of Astronomy, 2006, 37:55–69.
Boris A. Rozenfeld, “A Medieval Physico-Mathematical Manuscript Newly Discovered in the Kuibyshev Regional Library,”Historia Mathematica, 1975, 2:67–69; “The List of Physico-Mathematical Works of Ibn al-Haytham Written by Himself,” Historia Mathematica, 1976, 3:75–76.
Max Meyerhof, “ʿAlī al-Bayhaqī’s Tatimmat Ṣiwān al-Ḥikma. A Biographical Work on Learned Men of the Islam,”Osiris, 1948, 8:122–217, p. 155; Sabra, Optics (cit. note 7), p. xxxi; Rashed, Mathématiques infinitésimales (cit. note 10), p. 4.
Aydın Sayılı, The Observatory in Islam and its Place in the General History of the Observatory (Ankara: Türk Tarih Kurumu Basımevi, 1960), pp. 53–55; Marie-Geneviève Balty-Guesdon, “Le Bayt al-Ḥikma de Baghdad,” Arabica, 1992, 39:131–150, pp. 132–138.
For such criticism: Donovan A. Courville, “Limitation of Astronomical Dating Methods,”Kronos, 1975, 2:49–72; John M. Steele, “The Use and Abuse of Astronomy in Establishing Ancient Chronologies,” Physics in Canada, 2003, 59:243–248; Douglas J. Keenan, “Astro-Historiographic Chronologies of Early China Are Unfounded,” East Asian History, 2002, 32:61–68; reply in David W. Pankenier, “Caveat Lector: Comments on Douglas J. Keenan,” Journal of Astronomical History and Heritage, 2007, 10:137–141.