BEST LIGHT WILL BE AFTER DARK, DURING ECLIPSE.

Byline: Greg Bolt The Register-Guard

Imagine the light from all the sunrises and sunsets on Earth reflected back toward us from a big mirror in space.

That's pretty close to what will happen Wednesday night - weather permitting - when most of North America has a front-row seat to a celestial light show. A total lunar eclipse is expected to turn the moon a coppery red-orange, a fitting shade for the October full moon, which folklore often calls the "Blood Moon."

Lunar eclipses, which always occur during a full moon, aren't nearly as rare as solar eclipses and are visible over much larger areas. What's more, people on the West Coast won't even have to stay up late to watch this one.

The moon already will be in the Earth's dim outer shadow, known as the penumbra, when it rises shortly after 6 p.m. By the time totality starts at 7:23 p.m., the moon should be well above the horizon and the sky dark enough to see the wash of ruddy light that slips through the Earth's atmosphere to faintly shine back at us from our single satellite.

People will have plenty of time to catch the show. The moon stays in the Earth's inner shadow, or umbra, for 1 hour and 21 minutes of total eclipse, ending at 8:45 p.m.

"It's kind of fun to just watch it happen," said Sue Moe, a science teacher at North Eugene High School. "Just seeing that red when it gets in that total shadow is kind of cool because it makes it really red."

Local astronomy buffs plan to gather at the College Hill reservoir to watch the sky show. But any place with a good view of the eastern sky will do, although the farther from city lights you are, the more vivid the phenomenon will be.

Unlike a solar eclipse, it's safe to look directly at a lunar eclipse. And the naked eye works just fine, although a modest pair of binoculars can enhance the view and can give the moon a kind of 3-D effect as the Earth's shadow sweeps across its surface.

To get people warmed up for the sky show, Eugene amateur astronomer Jean Grendler will be showing actual moon rocks from her personal meteorite collection at Dot Dotson's camera store, 1668 Willamette St. in Eugene, from 2 p.m. to 4 p.m.

Grendler said she also plans to bring along a Mars rock. And she'll hand out moon and sky maps for eclipse viewers along with tips on taking pictures of the moon.

Lunar eclipses are particularly photogenic thanks to that characteristic reddish light. It's produced by light that slips around the edges of the Earth's disk along the line where sunrise and sunset are taking place.

The atmosphere bends the light so it falls on the moon. As it does at sunrise and sunset, the atmosphere also scatters the short wavelength light, which is blue, letting only the red, long wavelength light pass through and onto the moon.

"You'll see the shadow of the Earth go across the moon and cover it up, but there's still some light that's creeping sort of lens-like through our atmosphere," Moe said. "It's definitely quite a bit subdued from the regular full moon, but it is red, there's no doubt about that."

With so many astral curiosities on display, the lunar eclipse is a natural opportunity to teach children about how the solar system works. With a flashlight, a soccer ball and a softball you can set up a miniature sun, Earth and moon to demonstrate basic solar mechanics.

"It's a great visual to be able to explain to folks what really happens," Grendler said. "The Earth gets in between the sun and the moon, and casts a shadow on the moon."

Unfortunately, autumn eclipses too often end up teaching a lesson in Northwest meteorology instead of astronomy. Grendler said the last total eclipse visible here, in November 2003, was a complete washout and the one before that played peek-a-boo among the clouds, revealing only brief glimpses.

"So it's been quite awhile since we've had a clear view of an eclipse here," she said.

The forecast for Wednesday night is looking like patchy fog with some clouds, so the chances for good viewing remain up in the air, as it were. But sky watchers are hoping the clouds part long enough for a good look because this one will have to last them: The next total lunar eclipse doesn't come along until March 2007.