d, the interval between successive oppositions, when the Earth passes approximately between Saturn and the Sun, is 378.1 days, so that Saturn is well placed for observation during several months in each year. Opposition dates up to 1990 are April 8, 1982; April 21, 1983; May 3, 1984; May 15, 1985; May 27, 1986; June 9, 1987; June 20, 1988; July 2, 1989; and July 14, 1990.Like all the superior planets, that is all outwards from the Earth, Saturn moves for the greater part of each year eastward. Its average rate is about 1 in eight days. As it approaches opposition its motion seems to slow down and to stop all together for about 70 days before the opposition date. For a period that may be as little as 133 days or as great as 141 days, it then seems to move in a retrograde, or westward, direction before reaching another stationary point and resuming its eastward movement. This behavior does not indicate any real alteration in motion. The apparent regression is due to the fact that the Earth moving in a much smaller orbit at a greater velocity, is catching up with Saturn and passing it. Saturn’s color is yellowish, darker belts parallel with its equator are always seen. These belts are not nearly as attracting as those on Jupiter, nor do they show so much detail. Saturn’s greater distance and smaller size make it less easy to study than Jupiter, the beauty of Saturn’s rings system tends to divert attention from its disk, particularly when the rings are wide open, thereby hiding a considerable part of the globe.Saturn’s albedo, which is the proportion of incident light it reflects, is 0.61. The planet’s apparent magnitude, which is its brightness as it appears from Earth, depends largely upon the angle at which the ring system is displayed, largely because the rings are more reflective than the disk. When the rings are wide open, the magnitude attains -0.3, so that, of stars, only Sirius and Canopus appear brig...
