Friday, December 9
Brilliant Venus stands out in the southwest during early evening. The planet lies 20° above the horizon an hour after sunset and doesn’t dip below the horizon until after 7:30 p.m. local time, well after twilight comes to a close. At magnitude –4.2, Venus is the brightest object in the evening sky after the Moon. A telescope reveals the planet’s 18″-diameter disk, which appears two-thirds lit.
Saturday, December 10
After the Sun sets this evening, look low in the southwest for Mercury. For observers at 40° north latitude, the innermost planet lies 7° above the horizon 30 minutes after sunset. (It appears somewhat higher the farther south you live.) Binoculars will help you to pick the magnitude –0.5 object out of the twilight glow. Today marks the peak of Mercury’s evening apparition because it now lies at its maximum elongation from the Sun (21°).
Saturn passes behind the Sun from our perspective, a configuration astronomers call solar conjunction, at 7 a.m. EST. Needless to say, our star’s glare makes it impossible to see the planet. Saturn will return to view before dawn at the end of December.
