Nadir
The nadir is basically the anti-zenith - the point directly below the observer on the celestial sphere. It has an altitude of -90o in the horizontal coordinate system.
Nadir
The nadir (from Arabic nazir, "opposite") is the astronomical term for the point in the sky directly below the observer, or more precisely, the point in the sky with an inclination of -90°.
nadir
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Nadir
Related Category: Astronomy: General
(n´dr) [Arab.,=opposite], in astronomy, the point on the celestial sphere directly opposite the zenith, i.e., directly beneath the observer.
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Na"dir (?), n. [F., Sp., & It. nadir; all fr. Ar. nasiru's samt nadir, prop., the point opposite the zenith (as samt), in which nasir means alike, corresponding to. Cf. Azimuth, Zenith.] ...
Nadir
The point on the directly beneath an observer, 180° away in from the .
nadir: the point on the celestial sphere that is diametrically opposite the observer's zenith.
nautical mile: a distance (6080 feet or 1853 metres) determined as 1 arc-minute of longitude at the equator.
Nadir
The point on the celestial sphere diametrically opposite to the zenith. [S92]
Naked Singularity ...
Nadir -- The direction from a spacecraft directly down toward the center of a planet. Opposite the zenith.
NASA -- National Aeronautics and Space Administration.
Nadir
a term used to describe a point directly underneath an object or body.
Nebula
a cloud of dust and gas in space, usually illuminated by one or more stars. Nebulae represent the raw material the stars are made of.
nadir: The point on the bottom of the sky directly under your feet.
nanometer (nm): A unit of length equal to 10-9 m.
natural law: A conjecture about how nature works in which scientists have overwhelming confidence.
NADIR
The nadir is the point directly below an observer.
NAIAD
Naiad is a tiny moon of . It was discovered using NASA's Voyager 2 mission in 1989. It orbits 48,230 km from the center of Neptune and is about 58 km in diameter.
Nadir
The nadir is the direction pointing directly below a particular location . Since the concept of being below is itself somewhat vague, scientists define the nadir in more rigorous terms....
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celestial horizon That great circle of the celestial sphere formed by the intersection of the celestial sphere and a plane through the center of the earth and perpendicular to the zenith-nadir line. Also called rational horizon.
The detector is a rectangular block which is divided internally into 4 prisms, one which faces downward towards the planet, or nadir, one faces upward, away from the planet (zenith), one faces into the spacecraft (aft), ...
nadir
Naiad
naked-eye star
Nakhla meteorite
nakhlite
Naos (Zeta Puppis)
Nasmyth focus
National Astronomy and Ionosphere Center
National Optical Astronomy Observatories (NOAO)
National Radio Astronomy Observatory (NRAO) ...
Nadir drove out the Russians and confined the Afghans to their present home in Afghanistan. He launched many successful campaigns against Persia's old enemies, the nomadic khanates of Central Asia; most of them were destroyed or absorbed into Persia.
The instruments on the nadir equipment deck consist of a camera, thermal emission spectrometer, laser altimeter, and a radio transmission relay.
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 ). Nadir is not used very often in astronomy but people talk about their zenith all the time.
A spacecraft's altimeter sends coded radio pulses, or laser-light pulses, straight down to a planet's surface (the nadir) to measure variations in the height of the terrain below.
In the Battletech game series, a star's Nadir and Zenith are the standard hyperspace jump points for most interstellar spacecraft.
As you become acquainted with the sky you need reference points. Two points on the celestial sphere that are always used is the zenith (the point directly over your head) and the nadir (the point 180 degrees from the zenith.
is the angle by which the telescope is lifted above the horizontal (if it looks down, λ is negative). The two angles together can in principle specify any direction: φ ranges from 0 to 360°, and λ from -90° (straight down or "nadir") ...
Then the plumb line not only defines the zenith as already shown, but in a downward direction it defines the nadir, which is the point of the sphere directly below our feet.
In other words, when Orion rises above the eastern horizon, Cassiopeia climbs to her highest elevation in the northern skies, while Crux (or the Southern Cross) descends to its nadir in the southern skies.
nadir the point directly underneath nebula a collection of gas and/or dust
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