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Saturn

Saturn is known as the ringed planet even though it’s now know that both Jupiter and Uranus also possess rings. Don't bother trying to see them their unless you happen to be flying by one of these planets. The rings of Saturn are the only ones visible from the Earth. The problem with Saturn is that is almost twice as far from the Sun as Jupiter (9.54 a.u.), and smaller. Jupiter often has magnitude of better than -2 while Saturn's brightness, at its best, approaches zero. You are not going to see the Saturn's rings without at least a modest-sized telescope. When Galileo first gazed at Saturn through his telescope it looked a bit like Mickey Mouse's head; a disk in the middle attached to two smaller disks on the sides. It impossible to see anything like those glorious space probe photographs of Saturn if you are using binoculars.

What you will actually see through binoculars depends on the position of the rings, viewing conditions, power of your binoculars, your eyes and possibly your imagination. I generally see something that is not quite a circle, but more like a poorly made omelet.

Saturn, being farther from the Sun than Jupiter, has even a longer year. It moves around the Sun once every 29.5 years. So Saturn stays within the same constellation for several of our years. It has a synodic period of 378 days and its period of retrograde motion last for 138 days.

Except for its rings, Saturn’s composition is similar to Jupiter's, gaseous with a molten core. Being the least dense planet in the Solar System (less dense than water), Saturn is even more flattened than Jupiter, although this is difficult to see because of its greater distance. Saturn has one very large satellite named Titan that may be seen through binoculars. It is larger than the planet Mercury and revolves around the planet once every 16 days. All together, Saturn has 18 satellites, some of them discovered quite recently.

Let us assume that you own a telescope (and Saturn is one of the best reasons for buying one). The rings of Saturn are a system of very thin rings stretching out from the equator. The rings reach out to over 80,000 miles from Saturn's center and the distance from the planet's surface to the outer ring is greater than from planet's surface to its center. The rings are only about five miles thick, so when we look at them sideways they appear, if at all, as an extremely thin line. The rings are made up of icy material in chunks less than a few feet in size and maybe only a few inches. From the Earth they appear quite solid. Every 15 years or so we see the rings sideways. Over the next seven years, Saturn revolves around the Sun and gradually we will obtain a more head-on view of the rings. They become thicker and it is easier to distinguish the divisions between the rings. Then for the next seven years, the process is slowly reversed and the rings once again appear as a thin line. There are three rings in the Saturnian ring system. The inner ring is also called the dusky ring and it's the most difficult to see. It has a width of about 10,000 miles. After a gap of a few hundred miles comes the middle or bright ting. It is the widest, about 15,000 miles across. There is a 2,500-mile division between the middle and outer ring called Cassini’s division. The final and outer ring is about 10,000 miles wide.

Perhaps I have exaggerated the difficulties of observing Saturn and its rings, perhaps not. But I would be remiss without mentioning the rewards. Saturn's rings are still among the most beautiful features in the Solar System. You cannot with a small telescope obtain the technical excellence of photographs taken with the giant telescopes or the detailed beauty as seen from the various space vehicles, but no photograph will duplicate the thrill of seeing the rings with your own eyes. Their delicacy and grace easily turn all the pictures into crass cliches, unable to approach the improbable and very really object before you.


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