ASTR 101 Lecture Notes - Lecture 1: Celestial Pole, Solar Time, Precession
Document Summary
Speed of light (c: c = 3 108 m/s, c = 3 105 km/s. Light-year (ly: 1 ly is the distance that light travels in 1 yr. distance = speed time. 1: distance = 1 ly, speed = c, time = 1 yr, distance = speed time. 1 ly = c 1 yr (3 105 km/s) ( 107 s) 10 trillion km: distance to nearest star = 4. 3 ly. Earth: longitude: 0 to 360 , latitude: 90 to +90 , 90 : south pole, 0 : equator, +90 : north pole. Celestial sphere: right ascension: 0 to 360 or 0 hr to 24 hr, declination: 90 to +90 , 90 : south celestial pole, 0 : celestial equator, +90 : north celestial pole. Celestial sphere"s and earth"s daily motion: stars rise in the east and set in the west, hence, the celestial sphere rotates east to west. (if the earth were stationary and the.
