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An observer in the penumbra experiences a partial eclipse. An alternative definition is that the penumbra is the region where some or all of the light source is obscured (i.e., the umbra is a subset of the penumbra). For example, NASA's Navigation and Ancillary Information Facility defines that a body in the umbra is also within the penumbra. [2]
What is the penumbra during an eclipse. The second shadow is called the penumbra. According to timeanddate.com, the penumbra is the lighter outer part of the moon’s shadow. It is the portion of ...
Umbra, penumbra and antumbra. A point source of light casts only a simple shadow, called an "umbra". For a non-point or "extended" source of light, the shadow is divided into the umbra, penumbra, and antumbra. The wider the light source, the more blurred the shadow becomes. If two penumbras overlap, the shadows appear to attract and merge.
The umbra may be surrounded completely or only partially by a brighter region known as the penumbra. [23] The penumbra is composed of radially elongated structures known as penumbral filaments and has a more inclined magnetic field than the umbra. [24] Within sunspot groups, multiple umbrae may be surrounded by a single, continuous penumbra.
The definition of the term was originally derived from its primary scientific meaning, which is "a space of partial illumination (as in an eclipse) between the perfect shadow on all sides and the full light". [10] By analogy, rights that exist in the constitution's penumbra can be found in the "shadows" of other portions of the constitution. [13]
The small area where the umbra touches Earth's surface is where a total eclipse can be seen. The larger light gray area is the penumbra, in which a partial eclipse can be seen. An observer in the antumbra, the area of shadow beyond the umbra, will see an annular eclipse. [20]
A total penumbral lunar eclipse is a lunar eclipse that occurs when the Moon becomes completely immersed in the penumbral cone of the Earth without touching the umbra. [1] The path for the Moon to pass within the penumbra and outside the umbra is very narrow. It can only happen on the Earth's northern or southern penumbral edges.
A total eclipse occurs when the observer is within the umbra, an annular eclipse when the observer is within the antumbra, and a partial eclipse when the observer is within the penumbra. During a lunar eclipse only the umbra and penumbra are applicable, because the antumbra of the Sun-Earth system lies far beyond the Moon.