Bruce McClure has served as lead writer for EarthSky's popular Tonight pages since 2004. He's a sundial aficionado, whose love for the heavens has taken him to Lake Titicaca in Bolivia and sailing in the North Atlantic, where he earned his celestial navigation certificate through the School of Ocean Sailing and Navigation. He also writes and hosts public astronomy programs and planetarium programs in and around his home in upstate New York.
The 4 cross-quarter days fall between equinoxes and solstices. Halloween is the spookiest one – derived from a sacred festival of ancient Celts and Druids – coming as days grow short and nights long in the Northern Hemisphere.