4 articles for "Penumbra"

The partial shadow or darkness of an eclipse. An eclipsing body has both a full and a partial shadow. The penumbra is the partial shadow.

See also: ♦ Eclipse

The partial shadow or darkness of an Eclipse.

See also: ♦ Eclipse

Said of eclipses of the Moon, when the Moon approaches closely enough to the Earth's shadow to cause an appreciable diminution of light though it does not directly touch it. These are often termed appulses. They are not generally classed as eclipses, though from their close resemblance to eclipse conditions they often produce effects similar to those attending an actual eclipse. In fact to an observer on the Moon, the Sun would be partially eclipsed by the Earth.

See also: ♦ Eclipse ♦ Appulse ♦ Umbra ♦ Semiduration, Eclipse

The type of eclipse formed when the Moon enters into the Earth's penumbra, but not its umbra. We see a dimming of its light, but not a occultation of its disk. This is also called an appulse.

See also: ♦ Appulse ♦ Umbra ♦ Occultation