The document discusses astronomy and concepts related to measuring time. It describes the celestial sphere, which represents the apparent dome of stars in the sky, and notes key points on the sphere like the celestial poles and celestial equator. It also discusses different units of measuring time, including sidereal time based on the earth's rotation relative to the stars, apparent and mean solar time measured based on the sun's position, and time zones used around the world.

1. 8 th Grade Chapter 2 Lesson 3 Pgs. 75-78 For Student Use Only