Zenith

Zenith
Related Category: Astronomy: General
in astronomy, the point in the sky directly overhead; more precisely, it is the point at which the celestial sphere is intersected by an upward extension of a plumb line from the observer's location.

Zenith
For other uses, see Zenith (disambiguation).In broad terms, the zenith is the direction pointing directly above a particular location.

Zenith is also used for the highest point reached by a celestial body during its apparent orbit around a given point of observation.

Zenith
From LoveToKnow 1911
ZENITH (from the Arabic), the point directly overhead; its direction is defined by that of the plumb-line.

Zenith
The zenith is the point on the celestial sphere directly overhead the observer. It has an altitude of +90o in the horizontal coordinate system.

zenith
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Zenith distance. Astron. See under Distance. -- Zenith sector. Astron. See Sector, 3.

Zenith Angle
The angle from the outward normal of the to the object being observed.
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Definition: zenith: The point on the sky directly above the observer.
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Zenith is the point in the sky (on the "celestial sphere") directly overhead. Easy!
Just to give you a complete education, nadir is the point directly opposite the zenith, so it is below your feet (assuming you are standing ).

zenith point on the celestial sphere that is always directly above the observer regardless of his/her location. zodiac narrow belt of twleve constellation centered on the ecliptic.

zenith: (astronomical) the point on the celestial sphere vertically above the observer. In everyday parlance, ~ usually implies the highest point.

Zenith Distance
Angular distance on the celestial sphere measured along the great circle from the zenith to the celestial object. Zenith distance is 90° minus altitude.
Zeolite ...

zenithal hourly rate
the number of meteorites expected to be seen per hour when a meteor shower's radiant is at an observer's zenith; abbreviated ZHR
zodiac ...

ZENITH - Point directly overhead, as determined by the indefinite upward extension of a plumb line.

Zenith The point directly overhead (90° in altitude).
Zenith Hourly Rate A general guide to the expected intensity of any given meteor shower. It is a theoretical rate, assuming a radiant at the zenith with a sky limiting magnitude of 6.5.

Zenith
The sky directly overhead. An object 'transits' when its line of right ascension crosses the zenith.
Author: Dennis Bishop
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Zenith eclipse
Parnell successfully exposed a devious Conservative intrigue to associate him and his party with crime and violence through forged "Pigott Papers" from which he was vindicated in February 1890.

Zenith. The point directly overhead in the sky.
Good references for some of the above definitions include the annual Astronomical Almanac (Washington: U.S.G.P.O.); the Explanatory Supplement to the Astronomical Almanac, ed. by P. K.

Zenith The point on the meridian directly above an observer.
Zenithal Hourly Rate (ZHR) The theoretical hourly rate of meteors which would be observed at the peak of a shower, by an experienced observer, with the radiant at the zenith, ...

Zenith- the point on the celestial sphere directly overhead
Zodiac- the twelve constellations straddling the ecliptic through which the sun, Moon, and planets appear to move during the year ...

zenith
The point in the sky directly overhead.
zodiac
Twelve constellations through which the Sun travels. These constellations were important to ancient astrology but have no present day significance.

Zenith
Point in the Sky that is directly overhead.
Zero-Age Main Sequence (ZAMS) ...

Zenith. The point on the celestial sphere that lies directly overhead an observer, exactly 90 degrees away from every part of the observer's horizon.
Zenith distance. The angular distance of an object from the zenith.

Zenith
a point directly overhead from an observer.
Zodiac
an imaginary belt across the sky in which the Sun, Moon, and all of the planets can always be found.

zenith: The point on the sky directly overhead.
zero-age main sequence (ZAMS): The locus in the H-R diagram where stars first reach stability as hydrogen-burning stars.

ZENITH
An observer's zenith is the point directly overhead.
ZETA ORIONIS
Zeta Orionis (Alnitak) is a star at the eastern end of Orion's belt (in the Orion). Alnitak means belt. Alnitak is spectral Type O9.7Ib. It is also known as Alnitah.

Zenith Distance Scintillation. An always convenient sign to use is the naked eye scintillation or "twinkling" of stars. There are four attributes available for inspection: ...

Zenith - The point on the celestial sphere directly above an observer
Zero Point - The point from which the coordinates in a coordinate system are measured.

z is the zenith angle (900 - altitude)
k depends on the wavelength of the light and the elevation of the observer above sea level.

The name "Zenith Star" derives from the fact that star moves through the zenith at the latitude of the Royal Observatory in Greenwich, England.
Description of the Star ...

At about the zenith in winter sky, a trio of open clusters is bathed in the faint Milky Way of Auriga. They are paralleled M37 (NGC2099), M36 (NGC1960), and M38 (NGC1912) from east to west.

zenith (NASA Thesaurus / NASA SP-7, 1965) That point of the celestial sphere vertically overhead.
The point 180 degrees from the zenith is called the nadir.

Airy's Reflex Zenith Tube
Sunshine Recorder, circa 1876. ©National Maritime Museum, Greenwich, London This telescope was invented by Airy in 1851 to observe the positions of stars that pass almost vertically overhead.

Angular distance north or south of the prime vertical; the arc of the horizon, or the angle at the zenith between the prime vertical and a vertical circle, measured north or south from the prime vertical to the vertical circle.

Absolute magnitude The stellar magnitude any meteor would have if placed in the observer's zenith at a height of 100 km. Aphelion distance Abbreviation Q, distance of greatest heliocentric separation for a body in an eccentric orbit; Q=a(1+e).

Eltanin's high northerly position also takes it nearly through the zenith, the point overhead, as seen from London, causing it to acquire the now obscure name "zenith star." As a result the star was heavily studied.

5º N, and that means that an object at our zenith is at a declination of 42.5º N. This means that the Celestial Equator is located 42.5º south of our zenith.

A lunar standstill is just like a solar solstice, except that it refers to the northernmost and southernmost points of the zenith Moon over the globe of Earth.

Indeed, the roughly three centuries from the Scientific Revolution through the beginning of the modern era of solar system probes were essentially the zenith for belief in extraterrestrials in the West.

"We sailed on night after night, the weather growing colder and colder, and the North Star climbing towards the zenith.

The point on the celestial sphere that is directly over our heads at a given time is termed the zenith. The imaginary circle passing through the North and South points on our horizon and through the zenith is termed the celestial meridian.

The "Aha moment" is in his realization that since the rays of the Sun striking the Earth can be taken as parallel, that on any given day the solar zenith angle at solar noon of a point, A, ...

On October 23, 1975, this spacecraft was separated from the Orbiter, and landing was made with the sun near zenith, at 0517 UT, on October 25, 1975. A system of circulating fluid was used to distribute the heat load.

Remember, straight above your head (the zenith) is 90 degrees above the horizon. This object is NGC1582. It is over 1/2 of a degree across, and magnitude 7. 1/2 degree north and 3 1/2 degrees closer to the horizon brings us to NGC1664.

" Arcturus is the Zenith Star of the Hawaiian Islands. Using Hokule'a and other stars, the Polynesians launched their double-hulled canoes from Tahiti and the Marquesas Islands.

(a) Theoretical north-south line on the Earth's surface, or an extension of that line onto the night sky, connecting the observer's zenith with the celestial pole and the horizon. The meridian is used to state directional bearings.

Given that the radiant is low in the north-east, observers will need a site with a dark sky to the north and east and from there up to the zenith. Almost all the meteors will be observed some distance from the radiant point.

It increases from the zenith to the horizon and affects short wavelengths more than long wavelengths, so that objects near the horizon appear redder than they do at the zenith. The brightness of a star in the zenith will be reduced by only about 0.

5 and the radiant at the zenith. This is known as the zenithal hourly rate (ZHR) and is a measure of the concentration of material in the stream. The ZHR changes from year to year as the meteor stream constantly evolves.

polar triangle: the spherical triangle on the celestial sphere whose vertices are at the pole, the zenith, and a celestial body, with respective angles of the hour angle, the azimuth, and the parallactic angle.

The angle from (say) the eastern to western horizon (through the point directly overhead, the zenith) is 180 degrees.

It was seven degrees away from the zenith, meaning Syene must be seven degrees away from Alexandria as measured on the circle that is Earth's circumference.

The point on the celestial sphere directly overhead for an observer is the zenith. An imaginary arc passing through the celestial poles and through the zenith is called the observer's meridian.

As the Sun's stormy season arrived at its most recent zenith in the second half of the year 2000, ...

Refractors mounted on tripods can be comfortable to use while sitting in a chair if the object you are viewing is not near the horizon or zenith.

eyepiece height at zenith: 78" (no ladder needed - just a step stool)
total weight (without wheelbarrow handles): 192 lbs (87.2 kg)
portability: long distance - fits inside Ford Escort stationwagon with room to spare (left image below) ...

Can often be seen near the zenith in the mid-northern latitudes during the Northern Hemisphere summer. In about AD 14,000, Vega will become the North Star, owing to the 26,000 year precession of the equinoxes.

For more exact measurements of time, astronomers use the meridian, which is a circle on the celestial sphere that passes both through the zenith (the point directly overhead) and both celestial poles.

an imaginary circle on the celestial sphere that connects the zenith to the north (or south) celestial
Messier objects
the 107 bright deep-sky objects that belong to a catalog compiled by French astronomer Charles Messier in the 1700s ...