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Precession Circle

ConstellationsCentred on Draco (Northern Ecliptic Pole) and Dorado (Southern Ecliptic Pole)
Right AscensionCentred on:
18h00 (Northern)
06h00 (Southern)
DeclinationCentred on:
+66° 33' 39" (Northern)
-66° 33' 39" (Southern)
DimensionsEach precession circle has a radius of 23.44°, and describes an area of 1,726 square degrees
Optimum VisibilityOne of the Ecliptic Poles (Northern or Southern) is always visible
NotesThere are two precession circles on the celestial sphere, each marking out the path of the one of the Celestial Poles (northern and southern) around the corresponding Ecliptic Pole. The Northern and Southern Ecliptic Poles - points perpendicular to the plane of the Ecliptic - lie within the constellations of Draco and Dorado, respectively.

An imaginary circle traced out against the sky by the Earth's Celestial Poles (perpendicular to the Earth's equator) around the Ecliptic Poles (perpendicular to the plane of the Solar System). Each Celestial Pole moves very slowly around its circle, travelling about one degree every seventy years against the background of stars, under the influence of precession. The Northern Pole presently lies close to the star Polaris, making it the current Pole Star.


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