Alhazen is a lunar impact crater that lies near the eastern limb of the Moon's near side. Just to the south-southeast is the crater Hansen, and to the west is the Mare Crisium. The rim of Alhazen is nearly circular, but appears highly oblong when viewed from the Earth due to foreshortening. The inner walls and the crater floor are rugged and irregular. A low ridge joins the south rim of Alhazen with the nearby Hansen. The crater is named after the Muslim Medieval scientist, Ibn al-Haytham.
By convention these features are identified on lunar maps by placing the letter on the side of the crater midpoint that is closest to Alhazen.
Abū ʿAlī al-Ḥasan ibn al-Ḥasan ibn al-Ḥaytham (Arabic: أبو علي، الحسن بن الحسن بن الهيثم; c. 965 – c. 1040 CE), also known by the Latinization Alhazen or Alhacen, was an Arabscientist,mathematician, astronomer, and philosopher. Ibn al-Ḥaytham made significant contributions to the principles of optics, astronomy, mathematics, meteorology, visual perception and the scientific method. He spent most of his life close to the court of the Fatimid Caliphate in Cairo and earned his living authoring various treatises and tutoring members of the nobilities.
Ibn al-Ḥaytham widely considered the first theoretical physicist, and the earliest to discover that a hypothesis must be proved by experiments based on confirmable procedures or mathematical evidence—hence understanding the scientific method 200 years before Renaissance scientists.
In medieval Europe, Ibn al-Ḥaytham was honored as Ptolemaeus Secundus (the "Second Ptolemy") or simply called "The Physicist". He is also sometimes called al-Baṣrī after his birthplace Basra in Iraq, or al-Miṣrī ("of Egypt").