Star Motions
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Transcript: The apparent motions of the stars in the night sky depend on your position on the Earth’s surface. At a northern temperate latitude, the stars rise in the east and set in the west, and they travel on slanting paths across the sky. The north celestial pole sits in the northern sky and the elevation of the pole, or the bright star Polaris, is the same as your latitude on the Earth’s surface. Some stars are visible throughout the night as they orbit the north celestial pole; they are called circumpolar stars. If you were positioned at the Earth’s equator, stars would appear to rise directly out of the east and set directly into the west. The north celestial pole would be down on the horizon. That represents the region around which the stars are rotating in the night sky. If you moved to the pole of the Earth, the north pole of the Earth, the north celestial pole would be directly overhead; imagine yourself standing on the top of a spinning top staring upwards. All of the stars would be circumpolar; those near the horizon would be orbiting parallel to the horizon, and all stars would appear to circuit around the north celestial pole, or the star Polaris, which would be directly above your head.
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