Crossword clues for pole star
Wiktionary
alt. 1 (context star English) The star nearest a celestial pole of a planet. 2 A guide or guiding principle. n. 1 (context star English) The star nearest a celestial pole of a planet. 2 A guide or guiding principle.
WordNet
n. the brightest star in Ursa Minor; at the end of the handle of the little dipper; the northern axis of the earth points toward it [syn: Polaris, North Star, polar star, polestar]
Wikipedia
A pole star is a visible star, preferably a prominent one, that is approximately aligned with the Earth's axis of rotation; that is, a star whose apparent position is close to one of the celestial poles, and which lies approximately directly overhead when viewed from the Earth's North Pole or South Pole. A similar concept also applies to planets other than the Earth. In practice, the term pole star usually refers to Polaris, which is the current northern pole star, also known as the North Star.
The south celestial pole lacks a bright star like Polaris to mark its position. At present, the naked-eye star nearest to this imaginary point is the faint Sigma Octantis, which is sometimes known as the South Star.
While other stars' apparent positions in the sky change throughout the night, as they appear to rotate around the celestial poles, pole stars' apparent positions remain virtually fixed. This makes them especially useful in celestial navigation: they are a dependable indicator of the direction toward the respective geographic pole although not exact; they are virtually fixed, and their angle of elevation can also be used to determine latitude.
The identity of the pole stars gradually changes over time because the celestial poles exhibit a slow continuous drift through the star field. The primary reason for this is the precession of the Earth's rotational axis, which causes its orientation to change over time. If the stars were fixed in space, precession would cause the celestial poles to trace out imaginary circles on the celestial sphere approximately once every 26,000 years, passing close to different stars at different times. In fact, the stars themselves also exhibit proper motion, which causes a very small additional apparent drift of pole stars.
Usage examples of "pole star".
Polaris, the Pole Star, was far to my right, in the constellation of the Little Bear.
Ulbricht had just caught a brief but sufficient glance of the Pole Star and had established that they were in almost exactly the same place as they had been at noon that morning.
He composed the next bit of his story in his mind, which was going to be something about the tank needing to be orientated along a line dropped perpendicularly from the Pole Star to a baseline drawn between Mars and Venus, and was about to start trying to say it when he decided to give it a miss.
If you go up to Heaven I will follow you to the summit of the Pole Star, and if you go down into the earth I will follow you to the deepest pit of hell.
He drew dividends on his long labor of memorizing the Doughnut's timetable: in five minutes, by the taxi's chronometer, the Pole Star would make an angle with the orbit of—.
He picked out the Pole Star as a target, then loosened the safety catch of the firing switch in his glove.
She couldn't find the pole star, and then she suddenly realized that she didn't even know what the pole star for Mars was, or whether it even had one.
The Pole Star's captain had first demanded a golden Rider, twenty-five Earls in value, for each passenger.
Stars wheeled above, and he kept to a westerly course by keeping the pole star to his right.
The shift before the Pole Star was due, with Miss Gloria's relief, the timekeeper brought me two separation slips.