Revision as of 01:09, 31 October 2009 editRonhjones (talk | contribs)416,566 editsm Reverted edits by 69.117.211.88 to last revision by Alansohn (HG)← Previous edit |
Latest revision as of 07:08, 24 November 2023 edit undoSahaib (talk | contribs)Extended confirmed users, New page reviewers149,417 editsNo edit summaryTags: Mobile edit Mobile web edit Advanced mobile edit |
(11 intermediate revisions by 8 users not shown) |
Line 1: |
Line 1: |
|
|
#REDIRECT ] |
|
{{Mergeto | Pole Star |discuss=Talk:Pole Star#Merge proposal |date=January 2009 }}{{Unreferenced|date=January 2009}} |
|
|
{{otheruses6|North Star (disambiguation)|Northern Star (disambiguation)}} |
|
|
{{see|pole star}} |
|
|
|
|
|
|
|
{{Redirect category shell| |
|
] |
|
|
|
{{R from alternative name}} |
|
] of Polaris and neighbouring stars, taken from ]. In 2006 Polaris was 42' from the north celestial pole, and so does not lie exactly at the center of the concentric circular star trails.]] |
|
|
|
{{R mentioned in hatnote}} |
|
|
|
|
|
{{R with history}} |
|
The '''North Star''' is the prominent ] that lies closest in the sky to the ] and which appears (approximately) directly overhead to an observer at the Earth's North Pole. Currently, this is ], which lies about two thirds of a degree from the north celestial pole, at the end of the "bob" of the ] ] in the constellation ]. Polaris has a ] of 1.97 (second magnitude) making it the brightest star in the Little Dipper. A common method for locating Polaris in the sky is to follow along the line of the so-called "pointer" stars, the two stars farthest from the "handle" of the more easily spotted ] (part of the constellation ]). |
|
|
|
}} |
|
|
|
|
The North Star has historically been used for ], both to find the direction of north and to determine ]. It has been used by lost campers to find their way back home. It always appears due north in the sky, and the angle it makes with respect to the horizon is equal to the latitude of the observer. The North Star is visible only in northern hemisphere skies and so cannot be used for navigation south of the equator. |
|
|
|
|
|
Currently, there is no ] as useful as Polaris; the faint ] ] is closest to the south celestial pole. However, the constellation ], the Southern Cross, points towards the pole. |
|
|
|
|
|
A similar concept applies to other planets. |
|
|
|
|
|
|
|
|
|
|
|
==Past and future== |
|
|
Due to the ] the direction of the Earth's axis is very slowly but continuously changing, and as the projection of the Earth's axis moves around the ] over the millennia, the role of North Star passes from one star to another. Since the precession of the equinoxes is so slow, taking about 26,000 years to complete a cycle, a single star typically holds that title for many centuries. |
|
|
|
|
|
In 3000 ] the faint up star ] in the ] ] was the North Star. At magnitude 3.67 (fourth magnitude) it is only one fifth as bright as Polaris, the current North Star. |
|
|
|
|
|
] (also known as Alrai, situated 45 light-years away) will become closer to the northern celestial pole than Polaris around 3000 ]. |
|
|
|
|
|
==See also== |
|
|
{{nautical portal}} |
|
|
* ] |
|
|
* ] |
|
|
* ] |
|
|
* ] |
|
|
* ] |
|
|
* ] |
|
|
|
|
|
] |
|
|
] |
|
|
] |
|
|
|
|
|
] |
|
|
] |
|
|
] |
|
|
] |
|
|
] |
|
|
] |
|
|
] |
|
|
] |
|
|
] |
|