When observing Saturn, look for the Cassini Division, a dark gap between its two brightest rings. Through an 8-inch scope, note the rings’ brightnesses, color differences, and textures.
Markings on Saturn’s disk are subtle. Note any bright or dark spots compared to the belt or zone they’re in. From night to night, these features may change position.
Saturn’s zones appear off-white, slate-gray, or yellow. Saturn’s belts look bluish-gray, brown, and red. Such features stand out well through red, orange, or yellow filters. Occasional bright patches look best through a #58 (green) filter. Highlight the rings using a #56 (light green) or #82A (light blue) filter.
Uranus’ atmosphere is usually a featureless haze. Observers first reported details in 1870. Since then, other skywatchers have seen markings and belts. Through a small telescope, greenish Uranus appears as a slightly elliptical disk because of its rapid rotation. The planet moves slowly. It takes Uranus about 44 days to move the width of the Full Moon.
To the amateur astronomer with binoculars or a telescope, Neptune is no problem to find. At opposition, it displays a small blue disk that shines at about magnitude 7.7.
Even a large telescope won’t reveal much detail on Neptune, although you will see its largest moon, Triton, which shines at magnitude 13.5. The thrill of observing Neptune comes when you first spot it through your telescope. Because it lies farther from the Sun than Uranus, Neptune moves even more slowly. It takes approximately 85 days for the planet to traverse a Full Moon’s span.
Besides a telescope, it doesn’t take much to observe the planets. A good way to start is to check out “The Sky this Month” in each issue of Astronomy. Before you know it, you’ll have made seven new celestial friends.