Planetary Superstars

Time to dust off those forgotten telescopes: There's finally a real spectacle up there

By Bob Berman|Friday, October 1, 1999
People often imagine a telescope is a guaranteed ticket to an eye-opening space ride. But I'm going to let you in on astronomy's dirty little secret: There are only about a dozen glitzy places at which to point the thing.

Magnify a fuzzy galaxy or nebula, and you're still left with a colorless smear, only bigger. Gaze at cloud-covered Venus, and all you'll see is brilliant but featureless white. Mars is hardly more than an orange dot in small telescopes. Serious observers may find endless pleasure in the universe's subtler images, but those seeking a quick thrill often get discouraged. I'd guess that a million scopes are packed away in storage, forgotten by frustrated sky watchers.

The sky does offer a few true spectacles, of course. Sunlight etches dramatic shadows in the craters of a crescent moon. The stars of the Pleiades flicker like celestial fireflies. And right now, the night's true superstars, Jupiter and Saturn, both reach their biggest and brightest--and float next to each other in the sky. If ever there were a time to dig those telescopes out of the closet, this is it.

These planets are giants. Massive Jupiter could engulf 1,400 Earths. Counting its amazing system of rings, Saturn is more than 20 times as wide as our world. Because of their size, Jupiter and Saturn show intriguing detail even through a paltry 60 power magnification, and are bright enough to bulldoze their way through the most polluted urban skies.

Locating these largest, loveliest planets is a no-brainer. Use the three-second method. One: Look up any time after 9 p.m. Two: Pick out the sky's brightest star. Three: That's Jupiter. The only other bright star near it is Saturn. Both planets ride high in the sky and stay out all night.

A mere 100 magnification makes Jupiter appear twice as large as the moon seen with the naked eye. Its zebra-striped cloud belts are pale pink and salmon, not the electric reds and yellows of NASA's enhanced images, but they are crystal clear. Sharp-eyed observers may also pick out white ovals and dark spots. In 1610, when Galileo trained his spyglass on Jupiter, he was startled to see four prominent satellites circling the planet--proof that Earth is not the center of all motion. One of the satellites, Io, whips around Jupiter so fast it visibly changes position over the course of an evening.

As for Saturn, look for the ink-black Cassini division, an empty gap in the middle of the pale yellow rings. The division is named for Italian-born astronomer J.D. Cassini, who first recognized an astounding phenomenon never before seen on Earth or in the heavens: a globe encircled by a set of rings. Gravity from Saturn's moon Mimas creates the empty band that divides the rings in two. Unless you bought your telescope at a toy store for under $30, you have a better instrument than Cassini did in 1675.

Saturn's rings are a marvel of celestial engineering, 160,000 miles in diameter but only 70 feet thick. Right now the rings present a fuller view than they have all decade, making the planet especially bright and spectacular. It's one of the few telescopic sights that really knock you for a loop.
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