Maragha models
Also: Maragha school, Tusi couple, Ibn al-Shatir models
Geometric devices developed by medieval Islamicate astronomers to repair problems in Ptolemaic planetary theory. Closely matching devices later appeared in Copernicus, while the precise transmission path remains under study.
Astronomers associated with Maragha and later observatories devised geometric ways to model planetary motion without some of the features they found physically objectionable in Ptolemy. The Tusi couple is the best-known device; Ibn al-Shatir later constructed revised lunar and planetary models in Damascus.
Copernicus used closely matching mathematical devices. The strongest compact claim is model-specific: his Mercury construction is virtually identical geometrically to Ibn al-Shatir’s. Specialist work treats the similarities as evidence that technical knowledge traveled, while the documents needed to reconstruct every step of the route have not been found.