PCS 181 Lecture Notes - Lecture 5: Apparent Magnitude, Star Formation, Angular Momentum
Document Summary
Celestial sphere is representation of sky around earth. Earth is at the center of its sphere. When we look at the sky, we see half of the celestial sphere (bowl shape); because of rotation, what we see in the sky is based on time and our location. Horizon: a horizontal plane that appears to separate the earth from the sky. As earth rotates, sky rotates opposite way. Sky appears to rotate around ncp (or scp) Earth is tilted (23 degrees) to the plane of solar system, therefore celestial sphere is tilted by same amount. Sky after 6 hours (quarter of 24 hours); north star (polaris) Stars near the north celestial pole never set (we call these: circumpolar stars) We cannot see stars near the south celestial pole. All other stars (and sun, moon, planets) rise in east and set in west.
