* Earth's Tilt: Our planet's tilt on its axis causes different parts of the Earth to face the sun at different times of year. This leads to different constellations being visible in each season.
* Location: Your location on Earth also plays a big role. Stars visible from the Northern Hemisphere may not be visible in the Southern Hemisphere, and vice versa.
However, there are a few stars that are considered circumpolar stars. These stars are so close to the celestial pole (the point in the sky that the Earth's axis points to) that they never set below the horizon as viewed from a particular latitude.
Here are some examples:
* Polaris (North Star): Visible from the Northern Hemisphere, Polaris is the most famous circumpolar star.
* Ursa Major (Big Dipper): While the entire constellation does move throughout the year, the two stars at the end of the Dipper's bowl (Dubhe and Merak) remain circumpolar for most of the Northern Hemisphere.
* Ursa Minor (Little Dipper): This constellation is also close to the North Star and remains visible year-round in the Northern Hemisphere.
Remember, even though these stars are always above the horizon, their exact position in the sky will change throughout the year.
