BİRİNCİ FEN · İKİNCİ BÂB · DÖRDÜNCÜ FASIL · Birinci Madde
Article One
It describes the common-perpetual sphere (felek al-mumassil) of Jupiter.
O Noble One! Know that astronomers have said: Of the seven planets in the heavens, the sphere of Jupiter is the sixth relative to the sphere of the Moon.
Located above the sphere of the Sun and renowned as one of the “superior spheres” (eflāk-i ulviye), there are three stars; Saturn, Jupiter, and the midpoint of Mars – Jupiter, known as the mirror of felicity and bliss, is unique within its sphere and holds dominion over it. Due to this balance in its nature, it has been called "The Most Fortunate" (Sa‘d-i ekber).
Astronomical scholars (erbāb-i fenn-i hey’at) have determined three spheres for the star of Jupiter and explained their arrangement. The first sphere is at the center, within the zone (mıntıqā), at the poles, and in motion, resembling the sphere of the signs and is common-perpetual (mumassil).
The second is external to the center (ḥāriʿu’l-markez). Again, it is within the void of the common-perpetual sphere and between two parallel surfaces, carrying the supporting sphere. The third is the epicycle itself (felek-i tadwīr), upon which the star of Jupiter stands on one side, and as it moves around its center, this star rotates along with it.
The common-perpetual sphere of Jupiter is a “universal sphere” (kullī felek). And it is a spherical body surrounded by two parallel surfaces. Its upper surface touches the concave surface of the star of Saturn, which is above it; and its lower surface touches the convex surface of the star of Mars, which is below it.
This common-perpetual sphere, like the other spheres above and below it, primarily follows the movement of the greatest sphere, through the first motion (ḥarakat-i ūlā; ḥarakat-i kullī) [490], moving necessarily from east to west around the center of the universe. Secondly, with its own particular motion, it proceeds slowly from west to east by the amount of the movement of the eighth sphere (felekü’l-burūʿ). It appears as if it is moved by the movement of the eighth sphere. Consequently, its apogee, perigee, ascending node, and descending node progress one degree every seventy years with the eighth sphere. [43/a]