Alhazen's Problem - Wiktionary A mathematical problem in which lines drawn from two points in the plane of a circle must meet at a point on the circumference, making equal angles with the normal at that point. http://en.wiktionary.org/wiki/Alhazen's_problem
Camera Obscura alhazen a great authority on optics in the Middle Ages invented the first pinhole camera the Camera Obscura - and was able to explain why the images were upside down. http://inventors.about.com/od/weirdmuseums/ig/Illustrated-History-Photograph/Cam
Ibn Al-Haytham Biography From Answers.com b. Basra (Iraq), c. 965, d. Egypt, c. 1040 alhazen is considered the most important of the Arab physicists and therefore the chief physicist of the early Middle Ages. His http://www.answers.com/topic/alhazen
BBC - H2g2 - The Camera Obscura The first scientific description of the camera obscura was by the Arabian scientist, astronomer and mathematician, Ibn alHaytham (alhazen) (965-1038). http://www.bbc.co.uk/dna/h2g2/A2875430