In the Sky This Month

This is a great time of year to watch the Milky Way, the glowing band of stars that outlines the disk of our home galaxy. The Milky Way arcs high overhead around 9 or 10 p.m., before the Moon rises. You need dark skies to see it.

The brightest star of Pegasus, the flying horse, is Enif, from an Arabic name that means “the horse’s nose.” It’s to the upper right of the Great Square of Pegasus, which is in the east in early evening.

The 13th constellation of the zodiac rolls across the sky this evening. Ophiuchus is in the southwest at nightfall and begins to set after midnight. It covers such a huge area that it takes several hours for the whole thing to drop below the horizon.

The just-past-full Moon lights up the sky tonight. Since we’re getting close to the autumnal equinox, the Moon mimics the Sun and rises almost due east. It arcs high across the south later on.

Astronomers will be keeping an eye on a star near Orion’s Belt this month. The three-star belt is in the southeast at dawn, pointing up and down. If the star gets fainter, it could mean that a planet with a giant set of rings orbits the star.

The Moon is full tonight. Most years, September’s full Moon is the Harvest Moon. This year, though, October’s full Moon is closer to the autumnal equinox, so it takes the title. September’s full Moon is the Fruit Moon or Corn Moon.

Vega, one of the brightest stars in the night sky, passes high overhead this evening. From the middle latitudes of the United States, in fact, it passes directly overhead, which is the point in the sky called the zenith.

The planet Neptune is putting on its best showing of the year. It rises at sunset, is in the sky all night, in Aquarius, and shines brightest for the year. Even so, it’s so faint that you need a telescope to see it. It is near the Moon tonight.

Gamma Cephei forms the peak of the northern constellation Cepheus, the king. The constellation looks like a child’s drawing of a house, with Gamma Cephei at the point of the roof. The system consists of two stars and at least one planet.

To the people of Polynesia, the stars of Cassiopeia and Andromeda represented a dolphin, called Kwu. Cassiopeia formed its tail, while the brightest stars of Andromeda formed its fins. Andromeda’s fainter stars outlined the dolphin’s body.