Keywords: Tusi couple.jpg Tusi couple - 13th century CE sketch by Nasir al-Din Tusi Generates a linear motion as a sum of two circular motions Invented for Tusi's planetary model جفت طوسی رسم للعالم نصير الدين الطوسي حول نموذج مزدوجة الطوسي Online source http //wps prenhall com/esm_chaisson_astronomytoday_5/0 9185 1383966-content 00 html Pearson Prentice Hall Companion Website for Astronomy Today Original source Library of Congress Vatican Exhibit Vat Arabic ms 319 fol 28 verso Creator Nasir al-Din al-Tusi PD-old-100 Tusi-couple Old astronomical prints Medieval astronomy Medieval diagrams Nasir al-Din Tusi Illuminated manuscripts in the Library of Congress Manuscripts in Iran Islamic Astrology |