Mecca so that they may pray in the right direction, and to also be able to determine the correct times for prayer. In addition to the daily requirements, during the festival of Ramadan they must also know the moments of sunrise and sunset for fasting, and the location of the moon for the start of each month. The Book of Fixed Stars also follows a trend of increased production of illustrated manuscripts, as it is one of the oldest surviving treatises of its kind. This is not to say that this text was the first illustrated manuscript ever created, as there are many illustrated fragments that have been found and studied, most notably the Fustat fragments. The Fustat fragments are illustrated scraps of parchment that were found during excavations in Fustat, or Old Cairo. These fragments can be attributed to the stylings of the Fatimid period (969-1171), therefore dating the existence of astronomical illustrations to many years before the creation of the Book of Fixed Stars. The increase in illustrated manuscripts is also related to the advent of paper in the Islamic world in the tenth century. The increased availability of paper, which was much cheaper than parchment, drove the production of books in the Islamic world. Contents The book was thoroughly illustrated along with observations and descriptions of the stars, their positions (copied from Ptolemy's Almagest with the longitudes increased by 12° 42' to account for the precession), their magnitudes (brightness) and their color. Notably, al-Sufi improved upon Ptolemy's system for measuring star brightness. Instead of two brightness categories (‘more bright’ and ‘less bright’), al-Sufi employed three: AṢghareh (‘less’), Akbareh (‘greater’), and A’ẓameh (‘much-greater’). Ihsan Hafez has recorded 132 stars in al-Sufi's work not mentioned by Ptolemy. Al-Sufi's results, as in Ptolemy's Almagest, were set out constellation by constellation. For each constellation, he provided two drawings, one from the outside of a celestial globe, and the other from the inside. Al-Sufi's reasoning for this was that ‘the beholder might be confused if he saw the figure on the globe differing from what he sees in the sky’, demonstrating the book's use as a teaching device. Persis Berkelamp argues that each paired constellation was drawn slightly differently to encourage students to study the manuscript closely. Composition Introduction In his introduction, al-Sufi dedicates the work to his patron 'Abud al-Dawla and outlines the sources he has used to write the book.