Al-Sufi's Book of Fixed Stars

Al-Sufi's *Book of Fixed Stars* (964 AD) is a groundbreaking astronomical work that catalogs and describes stars based on their brightness and positions. Building on Ptolemy's celestial maps, Al-Sufi identified and depicted over a thousand stars, including many not visible to the naked eye today. He classified stars by their brightness and provided detailed illustrations, helping improve understanding of the night sky. His work was influential in preserving and advancing astronomical knowledge in the Islamic world and eventually influenced European astronomy, bridging ancient Greek models with later scientific developments.