Knowra Nasir al-Din al-Tusi Nasir al-Din al-Tusi Nasir al-Din al-Tusi was a 13th-century Persian polymath whose writings and institutions shaped astronomy, mathematics, philosophy, theology, and the sciences.
Hulagu Khan : Hulagu Khan was a Mongol ruler who founded the Ilkhanate and led the conquest of Baghdad in 1258. Al-Tusi served Hulagu and helped secure the resources for the Maragha observatory.
Ptolemaic astronomy : Ptolemaic astronomy is an Earth-centered system that models celestial motions with deferents, epicycles, and related devices. Al-Tusi worked within this tradition while criticizing problems in its mathematical models.
Ilkhanate : The Ilkhanate was a Mongol-ruled state in Iran and neighboring regions from the 13th to the 14th century. Its court patronage and political setting shaped al-Tusi’s later career.
Zij-i Ilkhani : The Zij-i Ilkhani is an astronomical handbook compiled at the Maragha observatory under al-Tusi’s direction. Its tables and observations made the observatory’s work available to later astronomers.
Mu'ayyad al-Din al-Urdi : Mu'ayyad al-Din al-Urdi was a Syrian astronomer and instrument maker associated with the Maragha observatory. He worked with al-Tusi on the observatory’s instruments and mathematical astronomy.
Deferent and epicycle : A deferent and epicycle are nested circles used in ancient astronomy to model apparent planetary motion. Al-Tusi revised circle-based planetary models rather than abandoning their basic geometry.
Islamic philosophy : Islamic philosophy is the philosophical tradition developed in societies shaped by Islam, engaging Greek thought and Islamic theology. Al-Tusi wrote influential works in this tradition, including commentaries and original arguments.
Copernican Revolution : The Copernican Revolution was the transformation of astronomy associated with placing the Sun, rather than Earth, at the system’s center. Similarities between Maragha devices and later European models have prompted debate about transmission.
Qutb al-Din al-Shirazi : Qutb al-Din al-Shirazi was a Persian polymath who wrote on astronomy, medicine, philosophy, and theology. As a student and collaborator, he carried Maragha astronomy into later scholarship.
Equant : The equant is a point from which a planet’s motion along a circle appears uniform in Ptolemaic models. Al-Tusi sought alternatives to the equant’s departure from uniform circular motion.
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