AS101 Lecture Notes - Lecture 1: International Astronomical Union, Constellation, Angular Diameter
Document Summary
September 29, 2011: when you look up at the stars you look out through a layer only about 100 km deep, with the naked eye, we can see more than 2000 stars plus the milky way, ancient civilizations named groups of stars called constellations, names were based on ancient heroes, gods, animals, shapes, and mythology was associated with them, many star patterns recognized today originated 5,000 tears with the babylonians, Just like a map of the earth is divided into countries, a map of the sky is divided into constellations: a constellation now represents not a group of stars but a section of the sky a viewing direction, any star within the region belongs to only that one constellations, the sky also contains some star groupings called asterisms, example, big dipper in the constellation ursa major (the great bear, great square of pegasus, the brightest stars in a constellation may actually be quite far away from each other.
