leo (redirected from Leonian)

Leo, in astronomy

Leo [Lat.,=the lion], northern constellation lying S of Ursa Major and on the ecliptic (apparent path of the sun through the heavens) between Cancer and Virgo; it is one of the constellations of the zodiac. The Egyptians, Babylonians, Arabs, and Greeks all represented this constellation as a lion; it may be the first constellation to be pictorially represented. The most famous star in Leo is Regulus (Alpha Leonis). The western part of the constellation is a curved line known as the Sickle; it represents the lion's head. The main constellation terminates in Denebola (Beta Leonis), the Lion's Tail. The meteor showers known as the Leonids appear to come from this constellation. Leo reaches its highest point in the evening sky in April.

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Leo

(Latin: “Lion”) In astronomy, the constellation lying between Cancer and Virgo; in astrology, the fifth sign of the zodiac, governing approximately the period July 23–August 22. Its symbol, a lion, has been associated with the Nemean lion slain by Heracles. The Nemean lion was considered invulnerable because its skin was impervious to arrows, but Heracles battered it to death with a club. Zeus put the lion in the sky as a constellation.

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LEO

(Low-Earth Orbit) A communications satellite in orbit 400 to 1600 miles above the earth. Being much closer than 22,282 mile-high geosynchronous satellites (GEOs), LEO signals make the round trip from earth much faster. Thus, low-powered "pizza dishes" and handheld devices can be used. LEOs are also better suited to interactive conferencing. Unlike GEOs, which travel at earth speed, LEOs revolve around the globe every couple of hours, and any single LEO is in view for only a few minutes. In order to maintain continuous communications, multiple LEOs must be used. From 48 to 66 LEOs are needed to cover the earth. See Iridium, Teledesic, GEO and MEO.

It Takes a Lot of LEOs

While the footprint of a GEO can cover the bulk of a continent, it takes many LEOs to cover the same area. Signals also travel to and from LEOs faster, making them more suitable for real-time applications than GEOs.

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Leo¹

a name for a lion, used in children's tales, fables, etc.

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Leo²

1. Astronomy a zodiacal constellation in the N hemisphere, lying between Cancer and Virgo on the ecliptic, that contains the star Regulus and the radiant of the Leonid meteor shower

2. Astrology

a. the fifth sign of the zodiac, symbol ♌, having a fixed fire classification and ruled by the sun. The sun is in this sign between about July 23 and Aug. 22

b. a person born during a period when the sun is in this sign

3. Astrology born under or characteristic of Leo

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leo [′lē·ō]

(mechanics)

A unit of acceleration, equal to 10 meters per second per second; it has rarely been employed.

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Leo [′lē·ō]

(astronomy)

A northern constellation, right ascension 11 hours, declination 15° north. Also known as Lion.

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LEO [′lē·ōor¦el¦ē′ō]

(aerospace engineering)

low-altitude earth orbit

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Leo

lion (July 23–Aug. 22). [Astrology: Hall, 315]

See : Zodiac

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1.		LEO - Low Earth Orbit
2.		Leo - 1. A general-purpose systems language, syntactically like Pascal and Y, semantically like C. ["The Leo Programming Language", G. Townsend, CS TR 84-7, U Arizona 1984].