Unlike a total lunar eclipse — when the moon passes centrally through the Earth’s dark shadow, or umbra, and the moon turns deep red in color — a penumbral eclipse merely grazes the umbra’s dusky outer fringes. The result is a slight brownish shading on the moon’s edge closest to the umbra. This sequence captured by Imelda Joson and Edwin Aguirre from Rockport, Massachusetts, shows the deep penumbral eclipse of March 14, 2006. This event was followed two weeks later by a 4-minute-long total eclipse of the sun, which Imelda and Edwin observed from Salloum, Egypt, near the border with Libya.
Credit: Imelda B. Joson and Edwin L. Aguirre
The moon will dip through the outer edges of Earth's shadow on Wednesday (Nov. 28) in a minor lunar eclipse, and you can watch the event live online.
The so-called penumbral lunar eclipse, which is a relatively minor darkening of the moon, will be primarily visible from East Asia, Australia, Hawaii and Alaska, but die-hard observers in the western United States and Canada will have the best observing chances at moonset early Wednesday morning.
The event coincides with the full moon of November 2012. Stargazers in the Eastern U.S. and Canada will miss the lunar show, but the online Slooh Space Camera will be providing live views of the penumbral lunar eclipse beginning with a preview at 7 p.m. EST tonight (000 Nov. 28 GMT) of November full moon from an observatory in the Canary Islands, off Africa's western coast. [Penumbral Lunar Eclipse Explained (Photos and Maps)]
Slooh's primary eclipse coverage from New Zealand and Hawaii begins Wednesday at 9:15 a.m. EST (1415 GMT). For a direct link to the Slooh eclipse webcast, visit: http://events.slooh.com/
Lunar eclipses occur when the moon is on the opposite side of the Earth from the sun. During eclipses, the moon passes through Earth's shadow, causing a darkening effect. Because the moon's orbit around Earth is tilted, lunar eclipses do not occur every month.
When the moon lines up exactly with the Earth and sun, it creates a total lunar eclipse and the moon can take on a bloody-red color. When only part of the moon passes through the Earth's shadow, it creates a partial lunar eclipse.
The Nov. 28 eclipse is known as a penumbral lunar eclipse because the moon will pass through the outer edge of Earth's shadow, a region called the penumbra. The darkest portion of the Earth's shadow is called the umbra.