A giant mythological soap opera stretches up the eastern half of the sky on October nights, encompassing five major constellations: Cassiopeia, Andromeda, Cepheus, Cetus, and Perseus. In the tale, Cassiopeia, queen of Ethiopia, claimed that she was more beautiful than the sea nymphs. The nymphs complained to the god Poseidon, who sent the sea monster Cetus to ravage the country. To save his people, King Cepheus chained his daughter Andromeda at the seashore as a sacrifice. At the last second, though, she was rescued by Perseus, who flashed the snake-topped head of Medusa at Cetus, turning the monster to stone.
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In the Sky This Month
October 24: M15
The globular cluster M15 is high in the southern sky at nightfall. Through binoculars, it looks like a fuzzy star. It’s actually a globe-shaped family of several hundred thousand stars that may contain a black hole at its center.
October 25: Vanishing Teapot
Sagittarius is disappearing into the evening twilight. Look for the outline of a teapot low in the south and southwest as darkness falls. The teapot is pouring its starry brew toward the horizon.
October 26: Teapot Cluster
Sagittarius, which resembles a teapot, is low in the south and southwest at nightfall. A giant star cluster lurks near the star that connects the lid and spout. Through binoculars, NGC 6624 looks like a fuzzy star. A telescope reveals many individual stars.
October 27: Cetus
One sure sign of autumn is the early evening appearance of Cetus, the whale or sea monster. As befits a whale, Cetus is huge, but its stars are faint and difficult to see. Cetus climbs into view in the southeast a few hours after sunset.
October 28: Friendlier Mars
The planet Mars stands about a third of the way up the southern sky at nightfall, shining like a bright orange star. It sets in the wee hours of the morning.
October 29: Dazzling Vega
One of the prime stars of summer continues to dazzle in the autumn sky. Vega is quite high in the west at nightfall. It’s the brightest member of the Summer Triangle.
October 30: Last-Quarter Moon
For the second time this month, the Moon is at last quarter. It is three-fourths of the way through its cycle of phases, headed toward “new” on November 7. There’s no special name for two quarter moons in the same month.