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Umbra
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Diagram showing a lunar eclipse with the Sun on the left, Earth in the center casting a shadow, and the Moon passing through Earth's umbra (total shadow) and penumbra (partial shadow). Diagram showing a solar eclipse, with the Sun, Moon, and Earth aligned. The Moon casts a dark umbra shadow on Earth for a total eclipse and a lighter penumbra for a partial eclipse.
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Nicolaus Copernicus. Nicolas Copernicus (1473-1543) Polish astronomer. In 1543 he published, forward proof of a Heliocentric (sun centered) universe. Coloured stipple engraving published London 1802. De revolutionibus orbium coelestium libri vi.
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Umbra

eclipse
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Umbra, that part of a shadow in which all light from a given source is excluded. The shadow from a point source of illumination is essentially all umbra, but that from a source of some size (as from the Sun) consists of a small umbra and a much larger partial shadow called the penumbra. Thus, in an eclipse of the Sun, the regions within the umbra experience a total eclipse and those within the penumbra, partial eclipse. The term is also used for the dark central portion of a sunspot. See also solar eclipse; lunar eclipse.