page_title: Avicenna
section_title: Astronomy and astrology
hierarchical_section_title: Avicenna / Other contributions / Astronomy and astrology
caption_attribution_description: English: Avicenna Old Mausoleum, this photo is taken and published in1950, the time that his Old Mausoleum is destroyed to move.
context_page_description: Ibn Sina, also known as Abu Ali Sina, Pur Sina, and often known in the West as Avicenna, was a Persian polymath who is regarded as one of the most significant physicians, astronomers, thinkers and writers of the Islamic Golden Age, and the father of early modern medicine. Sajjad H. Rizvi has called Avicenna "arguably the most influential philosopher of the pre-modern era". He was a Muslim Peripatetic philosopher influenced by Aristotelian philosophy. Of the 450 works he is believed to have written, around 240 have survived, including 150 on philosophy and 40 on medicine.
  His most famous works are The Book of Healing, a philosophical and scientific encyclopedia, and The Canon of Medicine, a medical encyclopedia which became a standard medical text at many medieval universities and remained in use as late as 1650.
  Besides philosophy and medicine, Avicenna's corpus includes writings on astronomy, alchemy, geography and geology, psychology, Islamic theology, logic, mathematics, physics and works of poetry.
context_section_description: Avicenna wrote an attack on astrology titled Resāla fī ebṭāl aḥkām al-nojūm, in which he cited passages from the Quran to dispute the power of astrology to foretell the future. He believed that each planet had some influence on the earth, but argued against astrologers being able to determine the exact effects.
  Avicenna's astronomical writings had some influence on later writers, although in general his work could be considered less developed than Alhazen or Al-Biruni. One important feature of his writing is that he considers mathematical astronomy as a separate discipline to astrology. He criticized Aristotle's view of the stars receiving their light from the Sun, stating that the stars are self-luminous, and believed that the planets are also self-luminous. He claimed to have observed Venus as a spot on the Sun. This is possible, as there was a transit on May 24, 1032, but Avicenna did not give the date of his observation, and modern scholars have questioned whether he could have observed the transit from his location at that time; he may have mistaken a sunspot for Venus. He used his transit observation to help establish that Venus was, at least sometimes, below the Sun in Ptolemaic cosmology, i.e. the sphere of Venus comes before the sphere of the Sun when moving out from the Earth in the prevailing geocentric model.
  He also wrote the Summary of the Almagest, (based on Ptolemy's Almagest), with an appended treatise "to bring that which is stated in the Almagest and what is understood from Natural Science into conformity". For example, Avicenna considers the motion of the solar apogee, which Ptolemy had taken to be fixed.
caption: Skull of Avicenna, found in 1950 during construction of the new mausoleum
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