The Shapes of the Seasons
The waning gibbous moon rises in the southeast a couple hours before midnight at week’s end, but Tuesday’s last-quarter moon does not crest the horizon until almost 2am.
The sun this week sets around 8:15, revealing the three brightest spring constellations: Leo the lion, marked by aquamarine Regulus; Boötes the herdsman, punctuated by rose-hued Arcturus, the fourth brightest star in the heavens; and Virgo, goddess of fertility, marked by Spica, the shaft of wheat in her outstretched hand.
By midnight, the constellations Lyra, Cygnus and Aquilla rise in the east. The three brightest stars of each, Vega, Deneb and Altair, make up the Summer Triangle.
Look midway between Boötes and Lyra for the constellation Hercules. While one of the great heroes of myth, Hercules is a rather indistinct grouping of stars, its brightest, Rasalgethi, a mere third-magnitude. What does stand out is a lopsided square of stars forming the figure’s body, an asterism called the Keystone of Hercules.
From sunset until a couple hours before sunrise, around 5:45 this week, golden Saturn treks across the heavens. Look for it high in the south-southeast at nightfall, to the southwest around midnight, and above the west horizon by 3am.
With the approach of sunrise over the weekend, look low in the east for Venus, Mercury and Mars, all less than two degrees from one another and forming a tight triangle. Venus is brightest and highest, with Mercury below and much fainter Mars to its left. Last week Jupiter was part of the melee, but now the gaseous giant has climbed almost 10 degrees higher. The planets are so tight against the horizon with the rising sun so close on their heels, you’ll likely need binoculars to track them down.