A penumbral lunar eclipse
-- so called because only the incomplete outer portion of the Earth's
shadow, or penumbra, falls across the moon -- is expected to reach its
deepest point at 7:50 p.m. ET on Friday, Oct. 18.
Unlike total eclipses, in which Earth's umbra -- the central region
of its shadow -- darkens the moon entirely, a penumbral lunar eclipse
involves only a slight dimming. Skywatchers should expect to see a much
more subtle sight -- with a shadow on the lower half of the full moon --
like the eclipse pictured below.
Weather permitting, viewers in the eastern part of the North American
continent should have a decent chance of seeing the end of the eclipse.
But the best show will be visible in Europe, Africa, and the Middle
East. For skywatchers in these parts of the world, the celestial
phenomenon will be observable during the overnight hours when the full
moon should appear brighter in the night sky. As PlanetSave noted, the penumbral lunar eclipse is expected to take place between 9:51 p.m and 1:50 a.m. GMT.
A map illustrates the expected visibility of the penumbral lunar eclipse during the October 2013 full moon.
Viewers along North America's West Coast may be out of luck, as the eclipse will occur during daylight hours there. The next lunar eclipse isn't expected until April 2014.
