BIG DOG AND THE DOG STAR

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By far the most common and conspicuous dragonfly is the green darner. This, fast, green-bodied dragonfly is most common in the East but can be found almost anywhere in North America that there is sufficient water.

Green darners can have bodies over three inches long and a wingspan up to about four inches across. But dragonflies are ancient insects—fossil remains date back to 250—300 million years ago—and some of the early varieties were enormous. In the fossil record are dragonflies with two and a half-foot wingspans!

Saturn's Razor-Thin Rings

In August, the rings of Saturn turn sideways—"edgewise"—to Earth for a second amazing time. But unlike in May, this time the sunlit face of them bursts into view and the planet soon after makes its closest approach of the year.

Getting a good view of Saturn's rings these next few months is tricky (much depends on having a good telescope and a night of steady atmosphere up on high). But if you like astronomy at all you should make the effort to see this. Not for over 40 years will similar views be visible! If you don't have even a small telescope of your own, seek out the public night of the nearest planetarium or amateur astronomy club (a huge listing of planetarium and club addresses and phone numbers can be found in the September issue of Sky & Telescope magazine, which should be available at newsstands and libraries by the time you read this).

What will you see under excellent conditions through a superb telescope? Until August 10, an oddly flattened yellow globe with one or two thin dark lines across it (the darkened, nearly edge—on rings and their shadow). Then, in the weeks after that date, the rings slowly come back into light and into enough tilt to become visible first as a needle, then as a thicker line of light. You may see moons of Saturn as little star-like beads lining up on that needle or string of radiance.

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