English to Arabic Science Astronomy & Space

To the two luminaries, i.e., the Sun and the Moon, whose motions never display stations or regressions, Eudoxus assigned three spheres each. Of these, the outermost, rotating in 24 hours from east to west on the polar axis, explains the daily rising and setting of the celestial body. The innermost sphere, in whose equator the celestial body is "embedded," completes one revolution in one year for the Sun, and in one synodic month (period between two new moons) for the Moon. It thus represents the motion of the celestial body along the zodiac. In other words, Eudoxus believed that not only the Moon but also the Sun had uniform zodiacal motions. This was despite the fact that, in about 430 B.C.E., the Athenian astronomers Meton and Euctemon had demonstrated their non-uniformity when they had discovered that the seasons had different durations. The middle sphere explains the recession of the Moon's nodes and, probably, a presumed but non-existent phenomenon of latitudinal motion of the Sun.


http://catalogue.museogalileo.it/indepth/AstronomicalSystems...