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Al-Sufi published Kitab al-Kawatib al-Thabit al-Musawwar (also commonly known as the Book of Fixed Stars) in AD 964 and dedicated it to Adud al-Dawla, the current ruler of Buwayhid at the time. This book describes forty-eight constellations and the stars that they are composed of. Within the Book of Fixed Stars, Al-Sufi compared Greek and Arabic constellations and stars to equate the same ones to each other. He also included two illustrations of each constellation, one showing the orientation of the stars from the perspective of outside the celestial globe and the other from the perspective of looking at the sky while standing on the earth. He separated the constellations into three groups: twenty-one northern constellations, twelve zodiac constellations, and fifteen southern constellations. For each of these forty-eight constellations, Al-Sufi provided a star chart that contains all of the stars that form the constellation. Each star chart names and numbers the individual stars in the constellation, provides their longitudinal and latitudinal coordinates, the magnitude of each star, and its location north or south of the ecliptic. Eight hundred thirty-nine years had passed since Ptolemy had published the Almagest, so the longitudinal placement of the stars within constellations had changed. To account for the new differences, Al-Sufi added 12° 42' to the longitudes Ptolemy had previously suggested for the placement of the stars. He also differed in Ptolemy by having a three leveled scale to measure the magnitude of stars instead of a two leveled scale. This extra level increased the accuracy of his measurements.

Al-Sufi organized the stars in each of his drawings into two groups: the stars that form the image that the constellation is meant to depict, and the stars that are in close proximity to the constellation but do not contribute to the overall image.

Al-Sufi identified and described stars that Ptolemy did not, but he did not include them in his star charts. He states at the beginning of the Book of Fixed Stars that his charts are modeled after those that were produced by Ptolemy, so Al-Sufi left them out of his charts as well.

Al-Sufi's astronomical work was used by many other astronomers that came soon after him, including Ulugh Beg who was both a prince and astronomer.