The longer, cooler nights of October offer some pleasant skywatching. Some of the signature constellations of autumn, including Pegasus and Andromeda, are in good view at nightfall and climb high across the sky around midnight. Under dark skies, look for the Andromeda galaxy, the most- distant object that is easily visible to the unaided eye — a whopping 2.5 million light-years away. On the planetary front, Venus is climbing into better view as the Evening Star, while Jupiter, the next-brightest light in the night sky, climbs into view in the dawn twilight by the middle of the month.
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In the Sky This Month
October 21: Almach
The colorful star system Almach climbs high across the sky on autumn nights. A telescope reveals one star that looks yellow-orange, and another that looks blue. Almach is one of the brightest stars of Andromeda, which passes high overhead early tomorrow morning.
October 22: Andromeda
Andromeda is one of the largest constellations. Its main figure is two streamers of stars that form a skinny V. But it takes some patience to find it. Right now, it is well up in the east and northeast at nightfall, and passes high overhead by midnight.
October 23: Big Neighbor
Our closest neighbor, the Moon, is 240,000 miles away—equal to 10 trips around Earth’s equator. The closest planet, Venus, the “evening star,” is always at least a hundred times farther. And the closest star system, Alpha Centauri, is a million times farther still.
October 24: Moon and Regulus
Regulus, the brightest star of Leo, the lion, will crouch close above the Moon at dawn tomorrow. Regulus actually consists of at least four stars, which are split into two close pairs. The system is almost 80 light-years from Earth.
October 25: Cepheus
Cepheus the king stands high in the north this evening, and looks like an upside-down child’s drawing of a house. It was passed down to us from ancient times through the Almagest, a famous text written almost 2,000 years ago by Claudius Ptolemy.
October 26: VV Cephei
Cepheus the king wheels high across the north on autumn evenings. It hosts one of the largest stars in the galaxy, VV Cephei. If it took the Sun’s place, it would swallow Mercury, Venus, Earth, Mars, Jupiter, and maybe Saturn.
October 27: Moon and Jupiter
Jupiter is in great view at dawn tomorrow. The solar system’s largest planet looks like a brilliant star a whisker to the upper right of the crescent Moon. Jupiter is the brightest object in the sky at that hour other than the Moon.