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кольцевое затенение (в результате дифракции света: The umbra, penumbra and antumbra are three distinct parts of a shadow, created by any light source after impinging on an opaque object.  wikipedia.org Nikitin-PRO) | |||
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| кольцевое затенение (в результате дифракции света: The umbra, penumbra and antumbra are three distinct parts of a shadow, created by any light source after impinging on an opaque object. wikipedia.org Nikitin-PRO) | |||