ASTR 101 1st Edition Lecture 3 Outline of Last Lecture I The Universe II Scale of the solar system III Cosmic calendar Outline of Current Lecture I Patterns in the Night Sky II The four aspects of cosmology III Constellations and planes Current Lecture Volcanoes 1 I Patterns in the Night Sky a The ecliptic is the path to the sun on the celestial sphere and the projection of Earth s orbit onto the celestial sphere b The meridian is the boundary between Eastern and Western halves of your local sky c The North celestial or South celestial poles do not move on the celestial sphere over the course of a day II The four aspects of cosmology 1 Motion of the planet Earth 2 Seasons 3 Lunar and solar eclipses 4 Planet in motion III Constellations and planes These notes represent a detailed interpretation of the professor s lecture GradeBuddy is best used as a supplement to your own notes not as a substitute a Constellations sort of map out the sky there are 88 official constellations b Celestial sphere stars look like they re on the same sphere but could be far apart and are various differences from the Earth c Galactic plane contains our milky way d Local sky objects altitude above the horizon and direction along the horizon specify its location on your local sky e We measure the sky using angles Since degrees of sun and moon are so close they sometimes cross each other f Angular size is inversely proportional to distance and directly proportional to physical size g They sky varies with both latitude and longitude you see a difference locally because of the time change h Altitude of the celestial pole your latitude i The North Star AKA Polaris is 50 degrees above your horizon due North Where are you At latitude 50 degrees North j At midnight the stars on our horizon are opposite the sun in the sky k The sidereal day is about 4 minutes shorter than the traditional solar day