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Issue date:
March 20-22, 1998

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How to find the right telescope

Before you buy, consider these tips from the editors of Sky & Telescope magazine:

Be sure you need a telescope. If you can't identify major stars and constellations, invest $150 in a chart and good binoculars.

When selecting features, consider what you'll be watching. For planet-gazing, you want a motor to track movement so you don't have to constantly re-aim your scope.

Forget magnification. You can use eyepieces to adjust power -- and you'll use lower powers most often anyway.

Spend wisely. A poor-quality scope will frustrate you, but you may not need the features of a $2,000 model. Beginners can get a good-quality scope for $200-$500; advanced viewers may spend $1,000.

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Stargazer Jim Flood got the Hubble Space Telescope to study the "starburst galaxy" NGC 1808, left. It's "easily the most impressive image" to result from NASA's formal program to involve amateurs, says Hubble analyst Max Mutchler.

An army of volunteer skywatchers

Every night, Hubble gets help in thousands of back yards.

Jim Flood still has his very first telescope, a little Sears model he got the Christmas he was 13. But a quarter-century later, Flood got a rare glimpse into deep space through his toy scope's ultimate successor: NASA's orbiting Hubble Space Telescope.

Flood joins a host of amateur astronomers who've shared the fruits of their hobby with Hubble's professional scientists. A chemist from Princeton, N.J., Flood participated in a program that let amateurs pick what Hubble would photograph. Countless other amateurs help Hubble every night: In an ongoing collaboration, they train their scopes on their favorite spot in the heavens and notify Hubble scientists when they see potentially significant activity.

What the amateur stargazers represent, says NASA's Ray Villard, is "a standing army of sky observers." And the good news, he says, is that "astronomy may be the one science where an amateur still can make a meaningful contribution."

Orbiting more than 300 miles above Earth since April 1990, Hubble has made almost 150,000 photographic exposures -- but even its high-tech eyes can't be everywhere at once. Enter the amateur astronomers. "They're not using Hubble themselves, but they're playing a critical role in research," says Hubble data analyst Max Mutchler.

For example, Mutchler says, amateurs may spend months watching a particular "variable star," one that grows brighter and darker by cycles and may periodically erupt as a nova. "When that star goes off," he says, "within an hour or two they can notify Hubble" so the telescope can be reprogrammed to photograph the unfolding celestial event.

Out of this world web sites

As an outgrowth of the formal program for amateurs, just concluded, Mutchler maintains an online "amateur astronomers kiosk" ( www.stsci.edu/~mutchler/amateur.html), which offers many other opportunities for backyard stargazers to collaborate with professionals. Among the listings: MarsWatch, which solicits observations of Mars to supplement Hubble's own.

As in Flood's case, amateurs may also provide the suggestions that inspire discoveries. A member of an astronomy club at Union College in Cranford, N.J., Flood, 39, had viewed countless heavenly bodies. But he would have had to travel to South America for a ground-based scope's best view of an object that fascinated him in pictures: an exploding spiral of stars 40 million light-years away in the constellation Columba. The flamboyant galaxy has a humdrum name: NGC 1808 (because it's the 1,808th listing in astronomy's New General Catalog).

Four years ago, Flood proposed that Hubble photograph NGC 1808. Of about 200 amateur proposals vying for a precious few hours on the telescope, Flood's was one of 13 chosen. In the middle of the night on Aug. 14, for 54 minutes, Hubble's cameras made images of Flood's chosen spot in the sky. Where was Flood during this once-in-a-lifetime observation? In bed, asleep, knowing it takes about six hours for Hubble's data to reach Earth.

The images of NGC 1808 show an exotic "starburst galaxy" in which innumerable stars are being born at once. The galaxy has spiral arms, like Earth's Milky Way, and a massive central star cluster (above, left) that may be 100 light-years across. A Hubble news release says the images Flood inspired will "allow astronomers to explore the complex structures in the starburst core of the galaxy for the first time."

Flood and his fellow amateurs can't compete with professional astronomers in terms of advanced training and hardware. But what they can do, Flood says, is "provide many eyes in brute force" -- and maybe catch a bursting star Hubble might otherwise miss.