The Book of Fixed Stars (by Abd al-Rahman al-Sufi)

The Book of Fixed Stars, by Abd al-Rahman al-Sufi, is a pioneering 10th-century astronomical work that cataloged and described stars and constellations. Building on earlier Greek knowledge, it includes detailed star maps and observations, identifying bright stars and their positions. Al-Sufi’s work improved understanding of celestial motions and clarified star brightness and appearance. It served as a fundamental reference for future astronomers in the Islamic world and Europe, bridging classical astronomy with medieval Islamic science. Overall, it’s a significant historical contribution that helped shape the study of the night sky.