Pictures: Lunar Eclipse "Preview"—What You'll See Saturday

Blood Red Moon

Photograph by Dennis Mammana, TWAN

A composite picture shows the stages of an August 2007 lunar eclipse before, during, and after totality-when the full moon is completely blocked from direct sunlight. Totality for the December 10, 2011, lunar eclipse will start at 6:05 a.m. PT and last until 6:57 a.m. PT. (See pictures from the previous total lunar eclipse in June.)

Rather than going completely dark, the moon takes on a deep reddish hue during a total lunar eclipse.

"As the entire moon passes through the Earth's shadow cast by the sun in space, sunlight scattering off our planet's dusty atmosphere and subsequently reflecting off the surface of the moon will make it appear to change color," said Raminder Singh Samra, an astronomer at the H.R. MacMillan Space Centre in Vancouver, Canada.

Expect to see the lunar disk go from dark gray during the partial phase to reddish orange during totality, he said.

Published December 9, 2011

Moon Over Hawaii

Photograph by Fred Espenak, TWAN

A composite picture shows the stages of a total lunar eclipse in July 2000, seen as the moon sets over Hawaii.

Lunar eclipses can occur only when the full moon, Earth, and the sun are aligned so that the moon crosses through Earth's shadow. (Watch a moon facts video.)

Due to the moon's tilted orbit around Earth, lunar eclipses happen only a few times a year, Samra said. The eclipse can be full or partial, depending on how much of the lunar disk falls in our planet's shadow.

Published December 9, 2011

Canadian Eclipse

Photograph by Yuichi Takasaka, TWAN

The stages of an eclipsing moon cut across the sky over Lumby, British Columbia, in a composite made of pictures taken over two hours in February 2008.

Although people in Europe and Africa won't be able to see the entire event, part of the December 10 lunar eclipse will be visible in the evening, local time, as the moon rises.

Published December 9, 2011

Lunar Lines

Photograph by Juan Carlos Casado, TWAN

Red bugloss plants, native to Tenerife in the Spanish Canary Islands, point like fingers at a lunar eclipse as it progresses across the sky in May 2003. The composite picture was taken on Teide, a dormant volcano.

At approximately 24,606 feet (7,500 meters) above the seafloor, Teide is the highest point in the Atlantic Ocean. (Watch a time-lapse video of the night sky over the Canary island of La Palma.)

Published December 9, 2011

Partial Eclipse

Photograph by Anthony Ayiomamitis, TWAN

Earth's shadow obscures only part of the moon in a composite picture of a partial lunar eclipse taken from Athens, Greece, in August 2008.

After Saturday's eclipse, sky-watchers are in for a dry spell—the cosmic lineup needed for a total lunar eclipse won't occur again until April 14, 2014.

The next partial lunar eclipse happens on June 4, 2012, when a chunk of the moon will appear to be gobbled up by Earth's shadow.

"The next few lunar eclipses that will occur will only be partial ones," the space center's Samra said, "so this will be our last chance to enjoy a total eclipse in quite some time."

(See more "Lunar Eclipse Pictures: When the Moon Goes Red.")

Published December 9, 2011