07/12/2026
Cassiopeia is a prominent constellation in the northern sky easily recognized by its distinctive "W" or "M" shape formed by its five brightest stars. Named after a vain queen in Greek mythology, it spans 598 square degrees, making it the 25th largest of the 88 official constellations. Because it is located near the north celestial pole, it is a circumpolar constellation from mid-northern latitudes, meaning it stays above the horizon and remains visible all night, every night of the year.How to Find ItLook North: Face due north after dark.Spot the "W": Search for the zigzag pattern of five bright stars embedded in the Milky Way.Find the Right Orientation: It looks like a "W" when low in the sky (late fall) and turns into an "M" when soaring high overhead (late winter/spring).Use the Big Dipper: Cassiopeia sits directly opposite the Big Dipper on the other side of Polaris, the North Star. When the Dipper is low, Cassiopeia is high.The Five Main StarsThe primary shape of the throne is formed by these five stars, listed from left to right when forming a "W":Segin (Epsilon Cassiopeiae): A blue giant star marking the front leg of the throne.Ruchbah (Delta Cassiopeiae): An eclipsing binary star whose name means "the knee".Gamma Cassiopeiae: An unpredictable eruptive variable star that flings off rings of mass.Schedar (Alpha Cassiopeiae): An orange giant and usually the brightest star in the constellation.Caph (Beta Cassiopeiae): A giant white star that completes the right side of the zigzag.Notable Deep-Sky ObjectsBecause Cassiopeia lies right across the rich band of the Milky Way, it is a goldmine for backyard telescopes and binoculars:Cassiopeia A: A famous supernova remnant that is the strongest radio source in the sky outside our solar system.The Owl Cluster (NGC 457): A beautiful open star cluster that closely resembles an owl with outstretched wings and two bright eyes.Messier 52 & Messier 103: Two rich, contrasting open star clusters easily found with minor magnification.The Heart and Soul Nebulae: A massive complex of glowing gas and dark dust where massive new stars are actively forming.The MythologyIn Greek lore, Queen Cassiopeia was the wife of King Cepheus and mother of Andromeda. Her undoing was her extreme hubris; she boasted that she and her daughter were more beautiful than the Nereids (sea nymphs). Offended, the sea god Poseidon sent a vicious monster, Cetus, to ravage the kingdom. To save their lands, the royals chained Andromeda to a rock as a sacrifice until she was rescued by Perseus. As a permanent lesson against vanity, the gods placed Cassiopeia in the sky tied to her throne, forcing her to spend half of every year hanging upside down. 🙃
This is the eighteenth episode in our series about the constellatio...