 Celestial Sphere: an imaginary sphere on which all the celestial objects would appear  Celestial object: any object in the sky that genuinely appears to rise in the east and set in the west  Includes the  moon,  sun,  stars, planets, and anything else in the nighttime or daytime sky

Path of a Star Stars that are overhead follow same path as the sun (rise in the east and set in the west) Stars that are close to Polaris (the Celestial North Pole) appear to move in circles around Polaris (circumpolar stars). These stars are in the Northern Sky Stars in the Southern Sky rise and set near the horizon because they are mainly visible in the southern hemisphere

 Apparent pattern that people use to mark the position of the stars  88 constellations  The sky is divided into these 88 regions each associated with a constellation  Constellations change with the season