The planet Jupiter shines like a brilliant star to the upper left of the Moon early tomorrow. Binoculars reveal its four largest moons. One of them is covered with giant volcanoes while another may have an ocean of liquid water beneath its icy crust.
Last Week's Stargazing Tips
September 19: Moon and Jupiter
September 18: Moon and Companions
The Moon has a couple of bright companions before dawn tomorrow. The brilliant planet Jupiter stands to the lower left of the Moon, with the fainter star Procyon a little farther to the Moon’s right or upper right.
September 17: John Goodricke
A star with a demonic reputation climbs the northeastern sky this evening. Algol represents the head of Medusa, a monster that’s part of the constellation Perseus. The star fades and brightens, which may have helped inspire its reputation.
September 16: Mars and Antares
The planet Mars is in the southwest as night falls, shining like a bright orange star. Not far to its left, look for equally bright Antares, a star that shines with the same orange color.
September 15: Last-Quarter Moon
The Moon reaches last quarter at 9:05 p.m. At last quarter, half of the side that faces Earth is bathed in sunlight, while the other half is in darkness. When the Moon is at last quarter it is leading Earth in our planet's orbit around the Sun.
September 14: Bright Arch
The curving body of Scorpius, the scorpion, and the teapot shape of Sagittarius hunker low in the south and southwest at nightfall. Cygnus, the swan, soars high overhead. And W-shaped Cassiopeia is about a third of the way up the northeastern sky.
September 13: Moon and Taurus
The Moon creeps toward the two most prominent star clusters late tonight, the Pleiades and the Hyades. Both are in the constellation Taurus. The Pleiades represents the bull’s shoulder, while the Hyades forms his face.