celestial pole


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celestial pole,

one of the two points at which the earth's axis of rotation intersects the celestial spherecelestial sphere,
imaginary sphere of infinite radius with the earth at its center. It is used for describing the positions and motions of stars and other objects. For these purposes, any astronomical object can be thought of as being located at the point where the line of sight
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. The celestial pole is important as a reference point in the equatorial coordinate systemequatorial coordinate system,
the most commonly used astronomical coordinate system for indicating the positions of stars or other celestial objects on the celestial sphere. The celestial sphere is an imaginary sphere with the observer at its center.
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; the celestial meridian passes through it, as do the hour circles of the stars. The polestar (see PolarisPolaris
or North Star,
star nearest the north celestial pole (see equatorial coordinate system). It is in the constellation Ursa Minor (see Ursa Major and Ursa Minor; Bayer designation Alpha Ursae Minoris) and marks the end of the handle of the Little Dipper.
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) lies within 0.5° of the north celestial pole. Although there is no bright star near the south celestial pole, the Southern Cross (see CruxCrux
[Lat.,=cross], small but brilliant southern constellation whose four most prominent members form a Latin cross, the famous Southern Cross. The long arm of the cross, terminating in the brightest member, Acrux (Alpha Crucis), points almost directly at the south celestial
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) points directly to it. The altitudealtitude,
vertical distance of an object above some datum plane, such as mean sea level or a reference point on the earth's surface. It is usually measured by the reduction in atmospheric pressure with height, as shown on a barometer or altimeter.
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 of the celestial pole in an observer's hemisphere is equal to the observer's latitude on the earth.

celestial pole

[sə′les·chəl ′pōl]
(astronomy)
Either of the two points of intersection of the celestial sphere and the extended axis of the earth, labeled N or S to indicate the north celestial pole or the south celestial pole.
References in periodicals archive ?
Please also notice that the values of observed celestial pole offsets (dotted series) are slightly different in both figures.
This ancient sacral preoccupation with taking supernatural direction from the spirit of the celestial pole, literally bringing an aspect of numinous heaven down to earth, like the practical use of the Dipper's handle as a clock-hand and the keying of lunar mansions to the culmination of circumpolar stars, survived on a liminal level to inspire seminal metaphors about charismatic potency, until by early imperial times both Taiyi and the Celestial Thearch di experienced a major resurgence of devotional interest.
Caption: To make the photograph used for the alignment process, you can attach the camera anywhere on the telescope tube or moving parts of the mount and point it toward the celestial pole. A sturdy camera mount is highly recommended.
The data jumps above 10 [micro]as and changes in trend below 10 [micro]as/a are detectable in celestial pole offset with accuracy better than 10 [micro]as and 16 [micro]as/a.
One good way to determine the exact location of the celestial pole is to use a fixed camera to make a time exposure of the sky and note the point that the stars appear to revolve around.
For the nutation (celestial pole offsets), P = dX + idY in celestial frame, very similar equations hold
All FCN models are constructed based on the analysis of the celestial pole offset (CPO) time series obtained from very long baseline interferometry (VLBI) observations of extragalactic radio sources.
Earth's rotation makes the stars appear to circle the north celestial pole in this July 1998 time exposure from the shore of Lake Zaboi in the Balkan state of Montenegro.
Rotating the mount around its polar axis tells the software where the mount's rotational axis is versus where the actual celestial pole is.
Better agreement with Very Long-base Interferometry (VLBI)-based celestial pole offsets (CPO) was achieved for the atmospheric/oceanic data from U.S.
Bootes lies behind Ursa Major, the Great Bear, and appears to be driving the Great Bear around the north celestial pole.
But the Southern Cross served as a good omen to Christian navigators, and it was practical, too: its long shaft points to within a few degrees of the south celestial pole. And in time navigators learned to find their way using many other bright southern stars.