Night sky to offer Md. full eclipse of moon

Astronomical event is first for state since October 2004

March 02, 2007|By Frank D. Roylance | Frank D. Roylance,Sun reporter

The last time Marylanders saw a total eclipse of the moon, the Boston Red Sox were wrapping up their first World Series victory since 1918.

That first-ever "World Series Eclipse" was Oct. 27, 2004, and it was under way as the Sox completed their four-game sweep of the Cardinals in St. Louis.

At sunset tomorrow, if the weather cooperates, we'll see another one, as the full March "Sap Moon" or "Crow Moon" rises over the eastern horizon about 6 p.m. It will already be in full eclipse - deep inside the northern half of the circular shadow Earth casts into space.

"Just like you and I cast a shadow on a bright, sunny day, the Earth is always casting a shadow. But you can't see it until something, this being the moon, passes through it," said Jim O'Leary, director of the Maryland Science Center's Davis Planetarium. "This a chance to see the Earth's shadow."

For observers in Maryland, the rising full moon will appear dimmer than usual as it climbs into the eastern sky. It may have an eerie, coppery color - a hue cast upon it by sunlight bent and filtered through Earth's atmosphere. The color can vary depending on how much volcanic dust and pollution is in the atmosphere.

If astronauts were watching from the moon's surface, they would look up and see the night side of the Earth as it slides in front of - and eclipses - the sun, leaving just a fiery ring of sunlight bent by the planet's slender envelope of air. All the gray lunar soil around them would be bathed in the odd, ochre light.

But for now, Earth is our only vantage point.

From the Science Center's rooftop observatory at the Inner Harbor's southwest corner, the darkened moon will appear to rise just to the right of the Marriott Waterfront Hotel.

In the dusky light at sunset, the dimmed moon may be hard to find, O'Leary said. "Until the sky gets dark, it could be a very dark eclipse."

Visitors to the observatory between 6 p.m. and 8:15 p.m. will have a variety of telescopes to choose from, he said.

Not far away, Baltimore's original "Streetcorner Astronomer," Herman Heyn, plans to set up his telescope on the Light Street promenade at Harborplace, weather permitting. But telescopes aren't a necessity.

"Both the naked eye and binoculars are fine for lunar eclipses," Heyn said. The eclipse will be visible anyplace on the East Coast where skies are clear and observers have a good view to the east.

A telescope will be handy for close looks at two planets that should also be easily visible. "Saturn is the bright, slightly yellowish, non-twinkling `star' above the moon," Heyn said. "Any [telescope] magnifying at least 25 times will reveal its beautiful ring."

Venus will be unmistakable, gleaming over the western horizon after sunset.

The complete lunar eclipse will be visible from Europe and Africa. But East Coast residents will have to settle for a moon that rises already in full eclipse, which will be at 5:56 p.m. in Baltimore. The period of totality will last about an hour after moonrise, with the deepest point of the eclipse at 6:20 p.m.

During totality, the northern edge of the moon's disk may appear somewhat brighter than the southern edge, the one that's deepest in Earth's shadow.

At 6:57 p.m., the moon will begin to emerge from the east side of the shadow, brightening first on its upper left edge. By 8:11 p.m., the partial phase of the eclipse will end, and the full moon will shine brightly again.

Lunar eclipses occur once or twice each year. But they're only visible from part of the planet. And not all of them are total.

The past four lunar eclipses have been partial, or "penumbral" eclipses, when some or all of the moon remains outside Earth's shadow, in partial sunlight.

If Maryland is clouded out for this eclipse, the next one will be Aug. 28. That one, too, will be total, but the moon will set in mid-eclipse.

"Put them together, and you'll see a full eclipse, from beginning to end, just six months separated," O'Leary said.

The next total lunar eclipse visible in Maryland from start to finish will be next Feb. 21.

As interesting as they are, lunar eclipses can't match the drama, spectacle and rarity of a total eclipse of the sun. That's when the new moon passes in front of the sun, sweeping its shadow across Earth and blotting out the sun to observers in its path.

There will be two partial solar eclipses this year, one March 19, visible from Asia, and the other in South America on Sept. 11.

The next time North Americans see a total solar eclipse will be Aug. 1, 2008, in extreme northern Canada.

But two will occur across the continental United States during the next 17 years.

The first will be Aug. 21, 2017, visible along a narrow path from Oregon to South Carolina. The second will be April 8, 2024, visible from Texas to the Eastern Great Lakes and Maine.

Both will be partial in Maryland.

frank.roylance@baltsun.com

For Maryland Science Center updates, call 410-545-2999.

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