Some stars and constellations are ever-present in the night sky; Polaris, for example, has served as a steady guiding light for millennia in the Northern Hemisphere.
But if you look closely at the sky night after night, you may notice that some stars move east to west from dusk to dawn, as well as change positions from season to season. For instance, Orion disappears from view for part of the year. So why do some constellations stay visible year-round, while others disappear and reappear depending on the season?
