The Celestial Sphere is an imaginary sphere that surrounds the Earth, onto which all celestial objects, like stars and planets, appear to be projected. This concept helps astronomers visualize the positions and movements of these objects in the night sky. The sphere is divided into two hemispheres: the northern and southern, with the celestial equator acting as the dividing line. Key features of the celestial sphere include the celestial poles, which align with the Earth's poles, and the ecliptic, the apparent path of the Sun across the sky throughout the year. This model simplifies the study of celestial navigation and the positions of constellations, such as Orion and Ursa Major.