Nasir al-Din al-Tusi
Nasir al-Din al-Tusi was the director of the Maragheh observatory, and made many new discoveries while he was there. Such discoveries include the Tusi-couple, a system based on geometry that includes a smaller circle within a larger circle that is twice the diameter of the smaller circle. The rotations of the smaller circle allow a specific point on the circumference to oscillate back and forth in linear motion. The Tusi-couple solved many issues with Ptolemaic's systems over planetary motion. Also, he helped astronomy become more accurate by discovering brand new stars as well as composing a star catalogue with detailed information about each star. Another notable work from Nasir al-Din al-Tusi was an astronomical book that contained detailed notes and observations about the movement of planets. Under Nasir al-Din al-Tusi, scholars from across the Islamic world came to the Maragheh observatory in order to further their studies in math, science, and astronomy. Furthermore, many new instruments were introduced to the observatory, which made him and his team's work a competitor to that of Europe.