AST101H1 Chapter 2: Chapter 2

• School: UTSG
• Department: Astronomy & Astrophysics
• Course: AST101H1
• Professor: Michael Reid

Document Summary

Constellations: a region of the sky with well-defined borders; the familiar patterns of stars merely help us locate the constellations. The celestial sphere: the imaginary sphere on which objects in the sky appear to reside when observed from earth. The celestial sphere allows us to map the sky as seen from earth. Four special points and circles on the celestial sphere. Every point in the sky belongs to some constellation: north celestial pole: the point directly over earth"s north pole. South celestial pole: the point directly over earth"s south pole: celestial equator: a projection of earth"s equator into space, making a complete circle around the celestial sphere. Ecliptic: the path the sun follows as it appears to circle around the celestial sphere once each year. It crosses the celestial equator at a 23. 5 angel, because that is the tilt of earth"s axis.