Al-Birjandi

Source: Wikipedia, the free encyclopedia.
al-Birjandi
al-Kashi
Academic work
EraIslamic Golden Age

Abdal Ali ibn Muhammad ibn Husayn Birjandi (

physicist who lived in Birjand
.

Astronomy

Al-Birjandi was a pupil for Mansur ibn Muin al-Din al-Kashi, a member at the Samarkand Observatory, otherwise known as

Ali al-Qushji's debate on the Earth's rotation.[2][3][4] In his analysis of what might occur if the Earth were moving, he develops a hypothesis similar to Galileo Galilei's notion of "circular inertia",[5] which he described in the following observational test (as a response to one of Qutb al-Din al-Shirazi
's arguments):

The small or large rock will fall to the Earth along the path of a line that is perpendicular to the plane (sath) of the horizon; this is witnessed by experience (tajriba). And this perpendicular is away from the tangent point of the Earth's sphere and the plane of the perceived (hissi) horizon. This point moves with the motion of the Earth and thus there will be no difference in place of fall of the two rocks.[6]

Works

Al-Birjandi wrote some more than 13 books and treatises, including:[7]

  • Sharh al-tadhkirah, a commentary on Tadhkira,
    Brill Academic Publishers
    .
  • Sharh-i Bist Bab dar Ma'rifat-i A'mal-i al-Asturlab (Commentary on "Twenty Chapters Dealing with the Uses of the Astrolabe" of Nasir al-Din al-Tusi; Persian.[11]
  • Risalah fi Alat al-Rasad (Epistle on observational instruments); in Arabic.
  • Tadhkirat al-Ahbab fi Bayan al-Tahabub (Memoir of friends: concerning the explanation of friendship [of numbers]); in Arabic.

Birjandi contributed to many different fields besides his commentaries. His works included studies of

ephemerides, instruments for astronomical observations, and cosmology. He also worked in determining the size and distance of planets that have been associated to Habib Allah.[1]

He also had works in the field of theology and made a series of almanacs in 1478/1479.

References