Below the W is Perseus (the Hero), a constellation containing two interesting objects.

First up is the star Algol, also known as the Demon Star because of the way it brightens and then dims every two days—a pattern the ancients thought was caused by a supernatural being.

Algol is a double star. When the smaller star moves in front of the larger star, some light is blocked and the star gets dimmer. When the smaller star is not in front of the larger star, we see all the light and Algol gets brighter.