A Changing of the Guard
As dusk gives way to darkness around 6:30, the sky comes alive with the constellations of winter and some of the brightest stars in the sky. High in the south stands Orion, facing west toward the bull Taurus. Behind the hunter come his hounds, Canis Major and Minor. Above Orion are the stick-like figures of the Gemini twins, and to their east is a loop of stars forming Auriga the charioteer. The luminaries of these constellations themselves loosely form the Great Winter Circle, in which the waxing gibbous moon sits right in the middle Wednesday the 17th.
While the winter constellations dominate the evening sky, those of spring are gathering to the east. At midnight, Leo the lion shines almost directly overhead, with Virgo and Boötes high in the east. As dawn draws near, Scorpius sprawls above the southern horizon.
The pre-dawn skies are also host to all the naked-eye planets.
Highest of the planets is Jupiter, rising around 9pm and midway between the bright star Regulus of Leo and Spica of Virgo. This is the best time of year for watching Jupiter. Even a modest telescope will reveal the gaseous giant’s equatorial bands and Great Red Spot as well as the planet’s four largest moons.
The next planet in line, Mars, doesn’t rise until 1am, as far to the east of Spica as Jupiter is to the west. Over the next few months, the planet rises earlier and grows brighter nearing its closest approach to earth in late May.
Saturn rises around 3am and is over the south-southeast horizon near dawn. Antares, the heart of the scorpion, is less than 10 degrees to the lower right. While the planet doesn’t climb especially high, its rings are tilted at a good angle for telescope viewing.
The coming sun begins to bleach the eastern sky by the time Venus crests the horizon, but she shines so bright she easily cuts through the glare. But you may have to scour the skyline to find Mercury, which is less than four degrees below the Morning Star at dawn Saturday.