ASTR 3 Lecture Notes - Lecture 2: Precession, Angular Diameter, Orbital Period
Document Summary
Constellation: a region of the sky, within official borders set in 1928 by the iau. The patterns of stars have no physical significance; stars that appear close together may lie at very different distances. Modern astronomers specify exact location of objects by a system of celestial coordinates. The celestial sphere if we imagine the sky around the entire earth, the sky above looks like a dome; we place. Earth in the center of this sphere b/c it represents our view from earth. North and south celestial poles are the points in the sky directly about earth"s n and s poles. Celestial equator: the extension of earth"s equator onto the celestial sphere. Ecliptic: the annual path of the sun through the celestial sphere, which is just a projection of earth"s orbital plane on the sky. Measure in angles, not distances: s1 = 60 arcmin, 1 arcmin = 60 arcsec, 1 = 3600 arcsec.
