ASTR 3 Lecture 2: Chapter 2: Discovering the Universe for Yourself
Document Summary
Constellation is a region of the sky with well-defined borders set in 1928 by the iau. Recognizable by a pattern or group of stars. Some patterns, like the winter triangle of sirius, procyon, and betelgeuse, span several. The patterns of stars have no physical significance! Modern astronomers use constellations as useful general landmarks, but specify the exact location. Stars that appear close together may lie at very different distances constellations of objects by a system of celestial coordinates. Stars at different distances all appear to lie on the earth"s celestial sphere. North celestial pole is the point directly over earth"s north pole. South celestial pole is the point directly over earth"s south pole. Celestial equator is a projection of earth"s equator into space. Makes a complete circle around the celestial sphere. Ecliptic is the sun"s apparent annual path around the celestial sphere. Crosses the celestial equator at a 23. 5 degree angle (tilt of earth"s axis)
