In the Sky This Month

The Moon will be at last quarter tonight, as it lines up at a right angle to the line between Earth and the Sun. Sunlight will illuminate half of the lunar hemisphere that faces Earth.

Draco is in the north and northwest as night falls, above the Big Dipper. One of the dragon’s highlights is NGC 5907, an unusually flat spiral galaxy that is well above the end of the dipper’s handle.

The Moon passes especially close to the bull’s bright orange “eye” tonight. Aldebaran is just an eyelash away from the Moon as they rise in late evening. The Moon will pass even closer to the star over the following hours.

NGC 7252, the Atoms for Peace galaxy, is in Aquarius. The constellation is low in the southeast at nightfall, and scoots across the south during the night. NGC 7252 looks like electrons orbiting the nucleus of an atom.

Wedged into a cozy space between the well-known constellations Andromeda, Aries, and Perseus is tiny Triangulum, the triangle. Its three brightest stars form a long, thin wedge. It rises in the northeast in early evening.

Two “dog stars” chase across autumn’s pre-dawn sky. The brighter one is Sirius, in Canis Major, the big dog. The other is Procyon of Canis Minor, the little dog. Both are high in the sky at first light, with Procyon far to the upper left of Sirius.

Look in the west as twilight fades this evening for one of the most commanding stars in the sky: Arcturus, in the constellation Bootes, the herdsman. It shines pale yellow-orange.

The Moon is swimming through the Celestial Sea, a group of constellations with a watery theme. Tonight, the Moon is near the border between Aquarius, the water bearer; Pisces, the fishes; and Cetus, the whale or sea monster.

The Harvest Moon lights up the sky the next few nights. It’s the full Moon closest to the fall equinox, which was yesterday. The Moon will be full at 9:52 p.m. CDT tomorrow night. But it will look almost the same on the nights before and after that.

Fomalhaut, the leading light of Piscis Austrinus, the southern fish, is quite bright. It rises to the lower right of the Moon tonight, and stands below the Moon around midnight. It’s in a fairly barren region of sky, which makes it easier to pick out.