In the Sky This Month

The constellation Sagittarius is low in the south-southeast at dawn. Its brighter stars form the outline of a teapot. The center of the Milky Way Galaxy is immersed in the faint “steam” rising from the teapot’s spout.

Spica, the brightest star of the constellation Virgo, rises below the Moon this evening, and the Moon will move closer to it during the night. Spica consists of two stars locked in orbit around each other. Both stars are bigger, brighter, and hotter than the Sun.

Earth’s atmosphere bends and splits sunlight, creating rainbows and other displays, including the rarely seen “green flash.” Under clear, clean skies it appears with the first burst of sunlight before sunrise or the last glimpse at sunset.

The Moon will grow dark tonight as it passes through Earth’s shadow, creating a total lunar eclipse. Almost all of the Americas will see the entire eclipse sequence, which begins with a partial eclipse starting at 12:09 a.m. CDT.

As the Sun drops below the western horizon, Earth’s shadow climbs into view above the opposite horizon. It forms a dark blue-gray band that climbs higher as the evening progresses. It’s also visible in the dawn sky, shortly before sunrise.

The fat gibbous Moon is in the east at nightfall. Regulus, the brightest star of Leo, is close below it. They move closer during the night and are almost touching as they set, before dawn.

The Sun’s closest planets are appearing close to each other in the early evening sky. Venus is the brilliant Evening Star. Mercury, the Sun’s closest planet, is close to its lower left this evening, but will slide above Venus over the next few nights.

The Pole Star points the way due north and serves as the hub of the sky – all the other stars appear to circle around it. Today, that hub is marked by Polaris. Several millennia ago, however, it was marked by Thuban, a star in Draco.

Mars is especially easy to find tonight. The planet stands close beside the Moon at nightfall and looks like a bright star. They will be a little farther apart as they set, in the wee hours of the morning.

M82, a galaxy that is a factory for exploding stars, loops high across the northern sky tonight. It stands to the upper left of the bowl of the Big Dipper as darkness falls. M82’s most recent supernova blasted into view a decade ago.