celestial poles

The North and South Celestial Poles are the equivalents in the sky of the North and South Poles on Earth. Earth’s axis joins the North and South Poles; extended northward it points to the North Celestial Pole, and extended southward it points to the South Celestial Pole. The North Celestial Pole is roughly marked by the star Polaris in the constellation Ursa Minor (the Little Dipper). Polaris is only three-quarters of one degree away from the true pole. To find Polaris, find Ursa Major (the Big Dipper) and extend the imaginary line joining the two stars known as the Pointers. There is no star marking the South Celestial Pole; the nearest star visible to the naked eye is Sigma Octantis. To find the South Celestial Pole, find the constellation of the Southern Cross and extend the imaginary line joining the two stars that form its longer arm.

Translations

poli celesti

celestial poles

The two points at which the extension of the Earth's axis of rotation cuts the celestial sphere. As a result of the precession of the Earth's axis the positions of the poles are not fixed but trace out a circle on the celestial sphere in a period of about 25 800 years. The north celestial pole revolves about a point in the constellation Draco and at present lies in Ursa Minor close to the star Polaris. The south celestial pole lies in the constellation Octans. See also pole star.

Celestial Poles

(north and south celestial poles), the two points on the celestial sphere at which it is interesected by the celestial axis, that is, by the line parallel to the earth’s axis of rotation and passing through the center of the celestial sphere. The celestial poles are independent of the diurnal rotation of the celestial sphere, but as a consequence of precession they slowly shift with respect to the stars along circles approximately 23.5° in radius. These circles have centers at the poles of the ecliptic, and a revolution is completed every 26,000 years. Because of nutation, the celestial poles execute minute oscillatory motions as they travel along these circles. These oscillations have an amplitude of approximately 9ʺ and a period of 18.6 years. In 1975 the north celestial pole was 51ʹ in angular distance from α Ursae Minoris, which is therefore called Polaris. In 5,500 years, the north celestial pole will be located near the star α Cephei.

celestial poles

The point on the celestial sphere where the earth's axis, if projected, would intersect the celestial sphere.

单词	celestial poles
释义	celestial poles celestial poles The North and South Celestial Poles are the equivalents in the sky of the North and South Poles on Earth. Earth’s axis joins the North and South Poles; extended northward it points to the North Celestial Pole, and extended southward it points to the South Celestial Pole. The North Celestial Pole is roughly marked by the star Polaris in the constellation Ursa Minor (the Little Dipper). Polaris is only three-quarters of one degree away from the true pole. To find Polaris, find Ursa Major (the Big Dipper) and extend the imaginary line joining the two stars known as the Pointers. There is no star marking the South Celestial Pole; the nearest star visible to the naked eye is Sigma Octantis. To find the South Celestial Pole, find the constellation of the Southern Cross and extend the imaginary line joining the two stars that form its longer arm. Translations poli celesti celestial poles celestial poles The two points at which the extension of the Earth's axis of rotation cuts the celestial sphere. As a result of the precession of the Earth's axis the positions of the poles are not fixed but trace out a circle on the celestial sphere in a period of about 25 800 years. The north celestial pole revolves about a point in the constellation Draco and at present lies in Ursa Minor close to the star Polaris. The south celestial pole lies in the constellation Octans. See also pole star. Celestial Poles (north and south celestial poles), the two points on the celestial sphere at which it is interesected by the celestial axis, that is, by the line parallel to the earth’s axis of rotation and passing through the center of the celestial sphere. The celestial poles are independent of the diurnal rotation of the celestial sphere, but as a consequence of precession they slowly shift with respect to the stars along circles approximately 23.5° in radius. These circles have centers at the poles of the ecliptic, and a revolution is completed every 26,000 years. Because of nutation, the celestial poles execute minute oscillatory motions as they travel along these circles. These oscillations have an amplitude of approximately 9ʺ and a period of 18.6 years. In 1975 the north celestial pole was 51ʹ in angular distance from α Ursae Minoris, which is therefore called Polaris. In 5,500 years, the north celestial pole will be located near the star α Cephei. celestial poles The point on the celestial sphere where the earth's axis, if projected, would intersect the celestial sphere. ThesaurusSeecelestial pole
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