You may be mooning for an eclipse Wednesday

If the clouds part, residents on the western, wetter side of the Pacific Northwest just might get a glimpse Wednesday night evening of the last total lunar eclipse to be visible from this corner of the planet until Dec. 20, 2010.

"It's not hopeless," said Carl Cerniglia, an optimistic forecaster at the National Weather Service in Seattle. Cerniglia said increasing clouds with showers are expected to move through, making it a challenge for anyone on the west side of the Cascades to see the eclipse.

"In Eastern Washington, you should be able to see it just fine," he said.

"From Seattle, the moon will just be rising in the eastern sky when it starts," said Toby Smith, an astronomer at the University of Washington. There usually are one or two lunar eclipses visible from somewhere on the planet every year, Smith said.

A total lunar eclipse occurs when the full moon passes into Earth's shadow and is blocked from the sun's rays that normally illuminate it. During an eclipse, the sun, Earth and moon line up, leaving a darkened moon visible to observers on the night side of the planet.

The moon doesn't go black because indirect sunlight still reaches it after passing through the Earth's atmosphere.

Because the atmosphere filters out blue light, the indirect light that reaches the moon transforms it into a reddish or orange tinge, depending on how much dust and cloud cover are in the atmosphere at the time.

Wednesday's total eclipse will last nearly an hour.

Earth's shadow is expected to blot out the moon beginning around 7 p.m. on the West Coast. Western sky gazers will miss the start of the eclipse because it occurs before the moon rises.

On Tuesday, Smith also was fielding calls about reports of a large fireball, presumed to be a meteor, which reportedly caused sonic booms as it entered the atmosphere and eventually hit the ground (making any remaining pieces "meteorites") in Adams County.

Several airplane pilots reported seeing the meteor.

The Federal Aviation Administration said a private pilot reported seeing the meteor hit the Earth in a burst of light near state Route 26 and Lind-Hatton Road about 5:45 a.m.

Surveillance cameras in the region captured a ball of light in the sky and then a flash illuminating the early-morning darkness.

Smith said he's withholding judgment as to what precisely happened, whether it hit the ground or even was a meteor.

Lunar eclipses aren't that interesting to scientists, he said, but he certainly encourages anyone to make the most of this event, or any astronomical event.

"The point is, there's a lot of interesting things going on up there," Smith said. "I'm glad if anything makes people look up and consider what's out there."

Unlike solar eclipses, which require protective eyewear, lunar eclipses are safe to view with the naked eye.

Later this year, in August, there will be a total solar eclipse and a partial lunar eclipse.