No functional celestial globe has come down to us that predates the coming of Islam. This celestial globe is a three-dimensional model of the universe, and is the third-oldest globe from the Islamic world. Only two others, created by an Andalusian astronomer, are older, and this is the oldest known globe from the eastern part of the Islamic world.
The globe differs from its Andalusian predecessors by the use of an alphanumeric system of notation (abjad) for numbering the stars within each of the 120 Ptolemaic constellations. Each of the 1,025 stars depicted is represented by a dot of inlaid silver, a technique that was unknown in the West. The diameter of the point varies depending on the magnitude of the star. The two hemispheres that make up the globe are joined along the Milky Way. The globe represents the final celestial sphere, that of fixed stars - a very precise version of Ptolemy's Almagest, a catalogue of stars written in Alexandria in the 2nd century AD. The difference between Islamic globes and what we know about ancient globes lies in the fact that Islamic globes represented the constellation from the front, instead of from the back.
Scientifically, this globe is exceptionally precise. It was created by a master astronomer who was capable, as the inscription engraved in the vicinity of the South Pole indicates, of recalculating astronomical calculations: "This globe comprises all of the constellations mentioned in the Almagest, after modification according to the time elapsed between the calculations of Ptolemy and year 540 of the Hejira: that is, fifteen degrees and eighteen minutes. Created by Yûnus Ibn al-Husayn al-Asturlabî in the year 539." The iconography of the constellations faithfully follows the model presented in the Book on the Constellations of Fixed Stars (kitab suwar al-kawakib) by 'Abd al-Rahman al-Sufi. The original of this work was lost, but we have been able to reconstitute it through a copy made by al-Sufi's son in 1099 and a manuscript from 1125 that explicitly refers to it. In addition to its remarkable scientific precision, the work is equally captivating due the quality of the engraving. Many of the clothed figures, including Cassiopeia, feature drapery comparable to figures in manuscripts. Their sinuous and stylized folds are characteristic of the art of the book that continued to develop into the mid-13th century, and even beyond, in the Arab part of the Islamic world.
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