Abd Al-Rahman Al Sufi was a Persian astronomer who was known as one of the outstanding practical astronomers during the Middle Ages.
In 964 C.E., he documented the Andromeda galaxy, the closest to the earth, and called it "little cloud". This was the first record of a star system outside of the earth's own galaxy.
Al-Sufi prepared charts of the heavens from his own observations and carefully measured them. His book "Kitah al Kawaatib" was considered a masterpiece on stellar astronomy. This book has been translated into many languages and it had a large influence on European astronomy. Many star names used today bear a resemblance to the Arabic names originally given by al-Sufi.