BİRİNCİ FEN · İKİNCİ BÂB · BEŞİNCİ FASIL · Üçüncü Madde
Article Three
It describes the epicycle of Mars, along with its form and movement.
O Noble One! Know that astronomical scholars have stated: Regarding the star Mars, they do not suffice with what has been described above to explain its conditions and the orderliness of its operation, but rather mention a small sphere that is not included in the earth, which they call an epicycle.
The epicycle is within the sphere of Mars’s deferent and is not included in the earth; it is a small sphere relative to its carrier sphere, being larger and wider than the sphere of the deferent of the sun. It carries the star itself and is adorned with it. It is fixed in the belt of the second oblique sphere, eccentric to the center. The diameter of the epicycle is tangent to the two surfaces of the carrier. The epicycle is a spherical body filled within, enclosed by a single surface. And within its own space, on the body of the oblique sphere, it continuously revolves from west to east with a specific movement, carrying along with it Mars, which is fixed on one side during this process. This aforementioned sphere, through its movement around its center from west to east, causes the star Mars to traverse approximately one degree of its belt of 360 degrees in a day and night, meaning it moves the star at a speed equivalent to the sun’s average velocity, completing its revolution once per year. This is what they call the variable motion of the star or the star's specific motion.
The star Mars is also enclosed by a surface; it is a spherical body filled with light and is spherical. It is fixed upon its epicycle body such that the surface of the star is tangent to the surface of the epicycle at a common point located on one side between the two poles of the epicycle. That is, the star is entirely within the body of the epicycle, its surface touching its surface. New astronomical experts have discovered and confirmed that, just as with the epicycle – as explained above – this aforementioned star also rotates ceaselessly around its own center with its unique motion in the direction of the epicycle, on one side of the carrier.