We see different constellations throughout the year because of Earth's orbit around the Sun. As Earth moves along its orbit, the night side of Earth faces different directions in space at different times of the year. This causes us to see different parts of the celestial sphere and thus different constellations in the night sky. Essentially, when Earth is on one side of the Sun, we see one set of stars, and six months later, when Earth is on the opposite side, we see a different set of stars. This annual shifting in our viewpoint is why constellations visible during summer are not the same as those visible during winter. Additionally, some constellations near the celestial poles are visible all year round, called circumpolar constellations, while others appear seasonally.
Earth's rotation also makes stars appear to move across the sky each night, but the yearly change in constellations is primarily due to the change in Earth's position in its orbit around the Sun. The Sun appears to move against the background of certain constellations called the zodiac constellations as Earth orbits, affecting which stars are visible at night.
In summary, the different constellations seen throughout the year result from the changing viewpoint caused by Earth's orbit around the Sun, exposing us to different sections of the celestial sphere during our yearly journey. This is a natural consequence of Earth's motion in space relative to the distant stars.
