This is a busy skywatching month, with a partial lunar eclipse on the night of the Harvest Moon, a morning appearance by Mercury, and close encounters between the Moon and all five planets that are easily visible to the unaided eye. The constellations of autumn climb to prominence, while some of the last of the summer constellations disappear in the evening wilight.
The full Moon of September is the Fruit Moon or Green Corn Moon. This year it’s also the Harvest Moon.
Apogee September 5
Perigee September 18
Moon phases are Central Time
The Sun, Moon, and planets move in front of the zodiac, the “pathway of animals.” The only inanimate member of the zodiac is Libra, the scales of justice. Libra arcs across the southern sky this evening. Its four main stars form a lopsided square.
Spica, the leading light of Virgo, stands close to the lower right of the Moon as night falls this evening. The brilliant planet Jupiter is to their upper right, completing a beautiful triangle.
The planet Jupiter is in great view tonight. It stands just a couple of degrees from the Moon. The planet looks like a brilliant star. For the hours they are in view, in fact, nothing outshines Jupiter except the Moon.
Venus will stand farthest from the Sun in the early morning sky tomorrow. At this time of year, though, its path tilts low above the horizon, so the planet doesn’t climb very high. Yet Venus is easy to pick out because it is the brilliant “morning star.”
Centaurus wheels low across the south on June nights. In fact, much of the constellation stays below the horizon. The brightest star in Centaurus that’s visible from most of the United States is Menkent, a name that means “shoulder of the centaur.”
Mighty Hercules stands high in the east as night falls at this time of year. The constellation’s brightest star represents the entire strongman: Its name, Kornephoros, comes from a Greek word that means “the club bearer” — Hercules himself.
The Moon has a familiar companion the next couple of evenings: Regulus, the heart of Leo, the lion. The bright star stands to the upper left of the Moon tonight, and closer to the right or lower right tomorrow night.
Cygnus, the swan, is a signpost for charting Earth’s path through the galaxy. As you face Cygnus as it rises in the northeast, you’re looking forward in our orbit around the Milky Way. The center of the galaxy is to the right, in Sagittarius.
Hydra, the water snake, wriggles across the southwest this evening. The galaxy M83 is near its tail, low in the south at nightfall. Under dark skies, some people can see the galaxy as a smudge of light. It is the most-distant object visible to the human eye, at about 15 million light-years.
A pretty little semicircle of stars crowns the sky on spring and summer nights: Corona Borealis, the northern crown. It’s high in the east as night falls, and stands overhead a few hours later. In a couple of months, it will be overhead at nightfall.
