عنوان مقاله [English]
نویسنده [English]چکیده [English]
In extant Islamic manuscripts we can find some observation reports of a black dot on the surface of the Sun. These reports add that this dot should be the planet Venus or Mercury, transiting over the Sun, showing that both of them are below the sphere of the Sun. The research made so far on Ibn Sina’s report shows that it might relate to a really observed Venus transit. Quṭb al-Dīn al-Shīrāzī (d. 1311 AD) in his astronomical books presents a list of some of these reports. But, being under the influence of numerical calculations of Muʾayyid al-Dīn al-ʿUrḍī (d. 1266 AD) on the distances and sizes of the planets, he believes that the sphere of Venus is above the sphere of the Sun. So he argues that it is impossible to observe a Venus transit even if it were below the Sun. Using the Ptolemaic rules of occultation and natural order, he criticizes the standard order of the planets. Finally he argues that what they have observed is nothing but a Sunspot.