When Galileo aimed his first telescope at Saturn he must have done a double take. Something was very peculiar about the shape of this slowest-moving planet: it seemed to consist not of one body but of three. With his primitive telescope, however, he couldn’t quite figure out what was really there.
He never did. His years of drawings depict a ball with ears attached, like a sugar bowl with two handles. It wasn’t until a half- century later (when telescopes approached the quality of today’s $100 department store variety) that something never before seen in nature astounded the world: a globe surrounded by unattached rings.
Right now, every telescope owner has the chance to discover what is arguably the most beautiful sight in the heavens at its best. Saturn floats in Capricornus, where Galileo first saw it, with its rings oriented just as they were back on that night in 1610. We can see exactly what Galileo saw, but with far better instruments.
For the past five years Saturn has been inching along the most southerly part of its 29.5-year orbit, condemning European and North American observers to view it through the blurry thick air near the horizon. Now, as it gets higher in the sky, it offers better prospects for the steady imagery vital for planetary viewing.
This month it’s closest to Earth, at its brightest and biggest, and visible most of the night. And its rings, which keep changing their orientation toward us, are now nicely tilted for our inspection. By the mid-1990s, however, they’ll appear edgewise. So this summer offers the best Saturn viewing until the century’s end.
Finding Saturn is no problem, even for those who experience consternation from constellations. Saturn now loiters in one of the zodiac’s bleakest sections, the dark alleyway that runs from Capricornus to Aries. With not a brilliant star in that whole district, Saturn’s brightness is a dead giveaway. Facing southeast, you’ll see it low but rising as darkness falls.
If the stars are really twinkling, resign yourself to a blurry night for planet watching. The same atmospheric conditions that make stars appear to shimmer frantically make planets seem as though they’re being viewed through boiling water. But if the stars are relatively steady, grab your scope. Don’t be put off by haze or even thin clouds. Bright city lights won’t interfere either; an urban site is fine for Saturn. Even modest telescopes reveal that the planet is every bit as beautiful--and as odd--as Galileo thought. For starters, Saturn appears decidedly oval, unlike the perfectly round sun and moon we’re accustomed to. It’s squashed at the poles because it’s the fluffiest planet, only 70 percent as dense as water. The planet’s lightweight substance is hurled equatorially outward by its rapid ten-hour rotation. The resulting bulge looks impressive, even through a small telescope perched nearly a billion miles away.
It’s fun to experiment with different magnifications while looking for the Cassini division, the jet black split between the rings. Or to count Saturn’s moons. Five or six of these adjacent little stars are easy to spot through a six-inch scope. Brightest is Titan, the only satellite with a substantial atmosphere.
Sometimes people claim to sort of see the rings with the naked eye. Depending on how polite you want to be, tell them no way. Which is also the best reply if someone tries to talk you out of viewing Saturn during this glorious season of its closest approach.