al-qirān al-Tūsī

E1022093

al-qirān al-Tūsī is a geometric device from medieval Islamic astronomy, devised by Nasir al-Din al-Tusi to generate linear motion from the sum of two circular motions and used to refine Ptolemaic planetary models.

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All labels observed (1)

Label Occurrences
al-qirān al-Tūsī canonical 1

Statements (46)

Predicate Object
instanceOf astronomical mechanism
geometric device
mathematical model
aim to avoid non-uniform equant motion in Ptolemaic theory
to reconcile uniform circular motion with observed planetary motion
alsoKnownAs Tusi couple NERFINISHED
appliesTo planetary models of Jupiter
planetary models of Mars
planetary models of Saturn
planetary models of Venus
basedOn composition of uniform circular motions
category geometric couple
coordinateSystem plane geometry
countryOfOrigin medieval Islamic world
describedIn works of Naṣīr al-Dīn al-Ṭūsī
developer Naṣīr al-Dīn al-Ṭūsī NERFINISHED
dimension two-dimensional mechanism
etymology "al-qirān" refers to coupling or conjunction
field astronomy
celestial mechanics
geometry
mathematics
hasPart diameter of the smaller circle
large circle
point on the diameter
smaller circle
historicalPeriod medieval period
inception 13th century
influenced Renaissance astronomy
geometric kinematics
late medieval astronomical models
languageOfName Arabic
mathematicalRepresentation sum of two sinusoidal functions with equal amplitude and opposite phase
motionType circular motion
linear oscillatory motion
namedAfter Naṣīr al-Dīn al-Ṭūsī NERFINISHED
city of Ṭūs via Naṣīr al-Dīn al-Ṭūsī NERFINISHED
property preserves uniform angular velocity in component circles
produces exact linear motion from two circular motions
tradition Islamic astronomy
usedFor eliminating the equant in Ptolemaic astronomy
generating linear motion from circular motions
modeling planetary latitude and longitude
refining Ptolemaic planetary models
usedIn Maragha school of astronomy NERFINISHED
non-Ptolemaic planetary models

Referenced by (1)

Full triples — surface form annotated when it differs from this entity's canonical label.

Tusi couple alsoKnownAs al-qirān al-Tūsī