BİRİNCİ FEN · İKİNCİ BÂB · ÜÇÜNCÜ FASIL · Beşinci Madde
Fifth Article
Concerning the places of Saturn (Zuhal)'s apogee and perigee, as well as its ascending and descending nodes.
O esteemed one! [42/a] It is known that astronomers have said:
Of the seven planets (seb’a-i seyyâre), each has a place of apogee. When a planet reaches its apogee, it is furthest from both its own sphere and the earth. The point directly opposite its apogee is called the perigee; when the planet reaches this point, it is closest to the earth and descends to its lowest point in its own sphere. As the planet approaches its perigee, its light strengthens; as it moves towards its apogee, its light weakens (hâbit). While on the first half of its sphere (nısf-ı evvel), it descends directly (hâbit) toward the perigee; in the second half (nısf-ı sâni), it ascends toward the apogee. The distance between these apojes and perigees is fixed and never changes. For if the apojes of the zodiacal sphere are known, then the corresponding perigees (mevâzi-i hadîdât) located directly opposite them are also determined. And conversely.
Similarly, when the places of the ascending nodes are known, the places of the descending nodes are also known; and conversely, with these two points known. For just as the perigees (hadîdât) correspond to the apojes (evcât) of the planets, so too do the nodes have a spring equinox counterpart. But the node (Cevzeher) is a point where the planetary spheres (eflâk-ı seyyâre) intersect with the zodiacal sphere. Thus, two places are created where two points of intersection occur, which are directly opposite each other. These intersecting points are then called the ascending and descending nodes. The ascending node is a place from which, when a planet departs, its latitude is in the northern direction. The point directly opposite it is called the descending node and the spring equinox (nübher). This is a place through which, when a planet passes, its latitude is in the southern direction. By “latitude” here is meant the distance of the planet north or south with respect to the sun’s orbit. However, Saturn's apogee, perigee, ascending node, and descending node are situated fifty degrees behind the signs of the zodiac due to its inclined sphere being very inclined northward from the belt of the zodiac. For the summits other than that of the moon, and the nodes, move in accordance with the slow movements of the fixed spheres.
In the year 1517 of the Roman era, Saturn’s summit was observed at 9.5 degrees of Sagittarius, and its perigee at 9.5 degrees of Gemini, directly opposite Sagittarius. The ascending node was observed at 9.5 degrees of Cancer, and its descending node at 19.5 degrees of Capricorn, directly opposite Cancer. But now, [at the time the author composed the *Mārifetnâme*], the Roman era has reached the beginning of April in the year 2069, which corresponds to the Hijri year 1170. Therefore, according to the consensus of most astronomers, the places of Saturn’s ascending and descending nodes – knowing that the planet's apogee, perigee, foot, and node points move one degree every seventy years – must be in the locations we will specify below. Accordingly, during the period from 1517 to 2069, the aforementioned planet's apogee, perigee, foot, and node points have moved approximately eight degrees. Therefore, Saturn’s apogee point is now at 17.5 degrees of Sagittarius, its perigee at 17.5 degrees of Gemini, its ascending node at 27.5 degrees of Cancer, and likewise its descending node at the same degree of Capricorn. Thus, the places of Saturn's apogee, perigee, foot, and nodes, as well as its node point, can be calculated and determined (easily) using the same method in future years.