The Great Bear; the familiar seven stars of the Big Dipper recorded by Ptolemy are visible in the rump and tail, but it can be noted that they are a mirror image of what we actually see. This is because al-Sufi provided provided two images for each constellation, one is the image we see in the night sky and the other is the image on the celestial globe. This image is a copy from the Bodleian Library.
The Book of Fixed Stars (in Arabic: كتاب صور الكواكب, translated: The Book of the Shapes of Stars), is a historic astronomical textbook written by astronomer Rahman al-Sufi (Azophi) in 964. Although the author is Persian, the book itself is written in Arabic. The book attempted to synthesize Claudius Ptolemy's Almagest (books VII and VIII) and the original constellations of Arabic traditional astronomy into a star catalog. It was written in the city of Shiraz, Persia (now Iran) for the patron and Buyid emir ‘Abud al-Dawla. This work was so influental that many manuscripts and translations have survived - the oldest surviving copy is kept at the Bodleian Library in England and dates to 1009.
Contents[]
The book itself details and narrates observations of the stars, their positions (copied from Ptolemy's Almgaest, with the longitudes increased by 12° 42' to account for the precession, their apparent magnitudes (brightness), and color. al-Sufi improved on Ptolemy's system for measuring star brightness - instead of using two brightness categories ("more bright" and "less bright"), al-Sufi used three: AṢghareh ('less'), Akbareh ('greater'), and A’ẓameh ('much-greater'). Ihsan Hafez recorded 132 stars in al-Sufi's work that was not mentioned by Ptolemy.
Just as Ptolemy's astronomical achievements were based on constellations, al-Sufi's research results were also presented in constellations. 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 behind 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.
| Northern constellations | Zodiac | Southern Constellaions |
|---|---|---|
| Ursa Minor | Aries | Cetus |
| Ursa Major | Taurus | Orion |
| Draco | Gemini | Eridanus |
| Cepheus | Cancer | Lepus |
| Boötes | Leo | Canis Major |
| Corona Borealis | Virgo | Canis Minor |
| Hercules | Libra | Argo Navis |
| Lyra | Scorpius | Hydra |
| Cygnus | Sagittarius | Crater |
| Cassiopeia | Capricorn | Corvus |
| Perseus | Aquarius | Centaurus |
| Auriga | Pisces | Lupus |
| Ophiuchus and Serpens | Ara | |
| Sagitta | Corona Australis | |
| Aquila | Piscis Austrinus | |
| Delphinus | ||
| Pegasus | ||
| Equuleus | ||
| Andromeda | ||
| Triangulum |