The shadow cast, in an eclipse, where the light is partly, but not wholly, cut off by the intervening body; the space of partial illumination between the umbra, or perfect shadow, on all sides, and the full light.
1) A partial shadow cast by the Earth or Moon that surrounds the umbra, or total shadow. During a total lunar eclipse, the Moon passes through the Earth's penumbra, then into the umbra where the Moon "disappears". Similarly, during a total solar eclipse, the Earth passes through the Moon's penumbra, and then into its umbra. 2) The region immediately surrounding the darkest portion, or umbra, of a sunspot. This region is darker and cooler than the surrounding photosphere, but lighter and hotter than the center of the sunspot.
The shadow cast when the incident radiation is partly, but not wholly cut off by an intervening body; the space of partial illumination between the umbra, or perfect shadow or all side and the full light. A marginal region on borderland or partial obscurity.
The area traced on a planet during an eclipse where only a portion of the eclipsed light source is blocked. Observers in the penumbral shadow of a solar eclipse, for instance, see only a partial eclipse. See also umbra.
Means, literally, "dim light". It most often refers to the outer shadow cast during eclipses, and defines the region of shadow which gives rise to a partial eclipse. It is also the lighter area surrounding the central region of a sunspot.
Literally "next to the umbra". (i) The shadow that results when only part of the bright object is occulted; e.g. an observer will see a partial eclipse when he is in the penumbra of the shadow of the moon. (ii) The lighter area surrounding a sunspot.
The lighter part of a shadow during an eclipse. An observer standing in the penumbra of a Solar eclipse will see a partial eclipse. This word can also mean the lighter part of a sunspot. See also umbra
The penumbra (Latin for almost-shadow) is the portion of a shadow that results from the source of illumination being only partially blocked. Penumbras occur only when the source of light is not a point source. As the sun is a visible disc, solar shadows have penumbras.
Penumbra is a file system module for the Linux kernel and a collection of userland tools for handling said file system. The Penumbra file system allows mounting already mounted directories onto a second directory.