The full moon will dip into Earth's shadow tonight (Oct. 18), producing a lunar eclipse that can be seen, but only for a short amount of time, IF you know when to look.
As long as the weather cooperates, skywatchers in Africa, Europe, western Asia, and the eastern parts of North and South America will get the chance to observe part of the southern portion of the moon passing into Earth's penumbra — the planet's outer shadow.
WHAT TO EXPECT
It may be tough to see because the shading will be subtle, but during the penumbral lunar eclipse, the moon will be partially in shadow for about four hours with the time of deepest eclipse occurring around 7:50 p.m. Friday. That's when you'll want to look closely.
At that moment, the Earth's outer shadow will cover 76.5 percent of the lunar disk. and you'll see a shadowy smudge on the southern edge of the moon, visible across the bottom half.
According to Space.com, the moon may also have a reddish tint to it at that time.
WHAT IS A PENUMBRAL ECLIPSE?
It's called a penumbral lunar eclipse because only the incomplete outer portion of the Earth's shadow, or penumbra, falls across the moon.
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. That's why it's often tough to tell when it's happening.