PHYS 1201 Lecture Notes - Lecture 2: Angular Diameter, Constellation, The Moons
Document Summary
The 88 official constellations cover the celestial sphere. Stars at different distances all appear to lie on the celestial sphere. The ecliptic is the sun"s apparent path through the celestial sphere. An object"s altitude (above the horizon) and direction (along the horizon) specify its location in your local sky altitude using angles & direction nsew. Zenith is a 90 degree altitude in the sky. Angular size = physical size x (360 degrees / 2 pi x distance) An object"s angular size appears smaller if it is farther away. Earth rotates west to east, so stars appear to circle from east to west. Stars near the north celestial pole are circumpolar and never set. We cannot see stars nears the south celestial pole. All other stars (and sun, moon, planets) rise in the east and set in the west. Altitude of the celestial pole= your latitude. Seasons depend on how earth"s axis affects the directness of sunlight.
