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eclipse

(Encyclopedia)CE5 A. Lunar eclipse B. Solar eclipse eclipse ēklĭpsˈ, ĭ– [Gr.,=failing], in astronomy, partial or total obscuring of one celestial body by the shadow of another. Best known are the lunar ec...

frequency

(Encyclopedia)frequency: see harmonic motion; wave. ...

Dyson, Sir Frank Watson

(Encyclopedia)Dyson, Sir Frank Watson dīˈsən [key], 1868–1939, English astronomer, b. Ashby-de-la-Zouch, grad. Cambridge. He was astronomer royal of Scotland (1905–10) and of England (from 1910). As director...

Algol, in astronomy

(Encyclopedia)Algol ălˈgŏl [key], famous variable star in the constellation Perseus; Bayer designation β Persei; 1992 position R.A. 3h07.7m, Dec. +40°55′. Algol's variation in apparent magnitude, from 2.06 t...

audio frequency

(Encyclopedia)audio frequency: see sound; radio. ...

radio frequency

(Encyclopedia)radio frequency, range of electromagnetic waves with a frequency or wavelength suitable for communication uses. Some of these waves serve as carriers of the lower-frequency audio waves; others are mod...

frequency modulation

(Encyclopedia)frequency modulation: see modulation; radio. ...

coronagraph

(Encyclopedia)coronagraph kərōˈnəgrăfˌ [key], device invented by the French astronomer B. Lyot (1931) for the purpose of observing the corona of the sun and solar prominences occurring in the chromosphere. Be...

automatic frequency control

(Encyclopedia)automatic frequency control: see automatic tuning control. ...

radio-frequency identification

(Encyclopedia)radio-frequency identification (RFID), a technology that uses radio waves to transmit data and uniquely identify an animal, person, or thing. An RFID system typically consists of a tag and a reader. T...