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Orion Nebula

(Encyclopedia)Orion Nebula, bright diffuse nebula in the constellation Orion; also known as the Great Nebula of Orion and cataloged as M42 or NGC 1976. It is located near the middle of the “sword” hanging from ...

prism

(Encyclopedia)prism, in optics, a piece of translucent glass or crystal used to form a spectrum of light separated according to colors. Its cross section is usually triangular. The light becomes separated because d...

seasonal affective disorder

(Encyclopedia)seasonal affective disorder (SAD), recurrent fall or winter depression characterized by excessive sleeping, social withdrawal, depression, overeating, and pronounced weight gain. SAD effects an estima...

aberration

(Encyclopedia)CE5 A. Spherical aberration: Light rays near the edge of the lens are bent more and brought to focus nearer to the lens. B. Chromatic aberration: Shorter wavelengths (higher frequencies) are bent m...

chiaroscuro

(Encyclopedia)chiaroscuro kyärōsko͞oˈrō [key] [Ital.,=light and dark], term once applied to an early method of printing woodcuts from several blocks and also to works in black and white or monotone. Today it i...

Finsen, Niels Ryberg

(Encyclopedia)Finsen, Niels Ryberg nēls rüˈbĕr fĭnˈsən [key], 1860–1904, Danish physician. He established in Copenhagen an institute of light therapy and wrote several books on his work. He received the 19...

Grimaldi, Francesco Maria

(Encyclopedia)Grimaldi, Francesco Maria fränchāsˈkō märēˈä grēmälˈdē [key], 1618?–1663, Italian physicist and mathematician. A Jesuit and professor at Bologna, he studied in detail and named the dark ...

Michelson, Albert Abraham

(Encyclopedia)Michelson, Albert Abraham mīˈkəlsən [key], 1852–1931, American physicist, b. Strelno, Prussia, grad. Annapolis, 1873, and studied at Berlin, Heidelberg, and Paris. He was professor of physics at...

McGinley, Phyllis

(Encyclopedia)McGinley, Phyllis, 1905–78, American poet, b. Ontario, Oreg. Her light verse treats aspects of modern life with humor and underlying seriousness. Among her best-known collections of verse are A Pock...

lighting

(Encyclopedia)CE5 Incandescent lamp CE5 Basic fluorescent lamp lighting, light produced by artificial means to allow visibility in enclosures and at night. For stage lighting, see scene design and stage ligh...