BİRİNCİ FEN · İKİNCİ BÂB · DÖRDÜNCÜ FASIL · Dördüncü Madde
**Article Four**
The speed of the Jupiter star, its true direction (istikāmat), its slowing (butū’), its stopping (ikãmet), its retrograde motion (ric’at); all these are the reasons it appears “confused” (hayret), describing its connections (irtibat) and proximity (ihtirāk) to the sun [493].
O esteemed one! It is known that astronomers have said: The acceleration, deceleration, straightness, stopping, and retrograde motion observed in the movements of the Jupiter star – these appearances of “confusion” (hayret) – are explained as follows: When this star reaches its highest point on its Epicycle, its own central movement aligns with the center’s movement of the Epicycle according to the rising of the signs, making the star appear to move swiftly. As the star inclines towards the Epicycle, it appears to move straight (müstakîmü’l-hareke). When the star mediates in the direction of descent on the Epicycle, it appears to move slowly (batî’u’l- hareke), because the star's own center is at that time descending and its movement becomes invisible.
When Jupiter is close to the Epicycle; its motion, contrary to the signs’ sphere relative to its own center, coincides with the carrier movement of the Epicycle’s center in a sequential (ale’t-tevâlî) manner. Since these two movements are opposite each other (in terms of direction), Jupiter appears to stop. When Jupiter is on the Epicycle; its own central motion exceeds that of the Epicycle's center, making it appear to move retrogradely. Once the star’s retrograde motion is complete and the two movements again coincide, they appear fixed (mukîm) a second time. After appearing to stop, it appears to be moving slowly again, because the star’s own center rises upwards, rendering its movement invisible. At that point, only the movement of the Epicycle's center becomes visible.
Following these stages, Jupiter’s slow motion returns to being straight and its swift motion is observed. Yet this star also completes its revolution within its own Epicycle without dispute. For the movements of stars and spheres occur around their own globes and within their orbits; therefore, they are all alike and their movements are regular. The station before Jupiter's retrograde motion is called the first *makãm*, and the one following it is called the second *makãm* (makãm-i sânî). The retrograde motion of the Jupiter star lasts four months, while its straight motion lasts eight months and nine days.
When this star’s inclined sphere is tilted one and a half degrees towards the southern and northern directions from the signs' belt; and when the Epicycle also appears at its apogee and perigee, being inclined towards the south or north from this inclined sphere, with a difference of two and a half degrees in latitude between them, Jupiter appears confused in its course and is named “confused.”
The explanation for the connection and proximity that befalls Jupiter relative to the sun, which illuminates the world, is as follows: Just as with Saturn, Jupiter’s own center is always at a distance equal to the middle of its Epicycle's sphere from its body. When Jupiter is located on the Epicycle's solstice point, it is always aligned with the sun. Because as the Sun's center moves away from the center of the Epicycle, the center of Jupiter also moves away by the same distance from the Epicycle’s middle apex. When the Sun opposes the center of the Epicycle, Jupiter finds itself descended to the Epicycle's Yerberi (hadîd-i tedvîr). Thus, Jupiter's nearness and remoteness from the luminous sun always occur while it is at the zenith of the Epicycle. Its facing the sun occurs when it is at the Epicycle’s Yerberide. Therefore, the time between Jupiter’s two approaches to the sun (within one revolution) is one year and thirty-three days [44/a].