The Book of Fixed Stars

[1] Following the translation movement in the 9th century AD, the book was written in Arabic, the common language for scholars across the vast Islamic territories, although the author himself was Persian.

[8] Although al-Sufi made his longitudinal calculations correct for the year 964 only,[8] the work remained highly influential, functioning as the standard text on Arabic astronomy to be consulted in all Islamic territories and faithfully copied for many centuries after its production.

[3] Since it was only correct for the single year of 964, the Book of Fixed Stars was intended to serve a broader educational purpose, rather than being concerned with the mathematical technicalities of astronomy.

[3] Medieval Islamic astronomers also drew from Sanskrit and Middle Persian sources to learn "methods for calculating the position of heavenly bodies, and for creating tables recording the movement of the sun, the moon, and the five known planets.

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.

These fragments can be stylistically attributed to the Fatimid period (969-1171), therefore dating the existence of astronomical illustrations to many years before the creation of the Book of Fixed Stars.

[11] 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.

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.

[8] These sources, including a number of treatises and objects which are now lost, serve as important indicators and records of the knowledge ('ilm) production at the time.

[8] The latter view can be explained by accounts of al-Sufi's drawing process, whereby the author carefully fitted a thin sheet of paper on top of a celestial globe and then directly copied the constellation outlines and star positions from the engravings.

The oldest manuscript was thought to be MS. Marsh 144 in the Bodleian Library, with a date of 1009 CE, and allegedly the work of the author's son, but this is now disputed, and has been re-dated to the end of the 12th century.

Book of Fixed Stars (Kitāb suwar al-kawākib al-ṯābita), by ‛Abd al-Rahman ibn ‛Umar al-Ṣūfī, dated 1125 CE, Baghdad (controlled by the Seljuks from 1055 to 1135). Doha Museum of Islamic Art MS 2.1998 . [ 5 ] Now thought to be the oldest surviving copy. [ 3 ]
The Great Bear . The familiar seven stars of the " Big Dipper ", recorded by Ptolemy , are visible in the rump and tail, but notice they occur as a mirror-image of what we actually see because Al Sufi provided two images of each constellation, one as we see it in the night sky and one as seen here on a celestial globe. The image is from the copy in the Bodleian Library , end of 12th century CE. (Bodleian Library MS. Marsh 144). [ 6 ] [ 3 ]
Orion , also as a mirror image. Copy from the Bodleian Library , end of 12th century CE. (Bodleian Library MS. Marsh 144). [ 7 ]
"Sign of Sagittarius" by al-Sufi in The Book of Fixed Stars , Artuqid Mardin , 1131 CE (TSMK, A. 3493) [ 15 ]