I put down down the snow shovel to give my back a rest yesterday evening and couldn’t believe what I saw. Or didn’t see. Where was Venus? I looked to the south above the tree line and the goddess was gone! Sweeping my gaze to the right I found her again much closer to the western horizon point and also much lower.
As 2013 gives way to the new year, Venus winds up its evening presentation as it prepares to transition to the morning sky. Catch it while you can. Each passing night sees the planet dropping ever closer to the horizon as its apparent distance from the sun shrinks. On January 11 it will pass through inferior conjunction as it glides between Earth and sun. Come the 12th, Venus nudges into the dawn sky – don’t expect to see it with the naked eye until around midmonth, when it’s far enough from the sun to bust through the twilight glare.
Though the planet is departing, don’t let it disappear without at least a glance through binoculars. As conjunction approaches, Venus gets as close (and as large) as it can get to Earth and displays a most attractive crescent phase. Even 7x binoculars will show its thinning sickle shortly at dusk. Tonight (Dec. 27) Venus measures nearly 1 arc minute in diameter or 1/30 the width of the full moon and shines brightly at magnitude -4.5.
As the planet drops ever lower, the crescent grows both larger and thinner. A few days before conjunction, a telescope will show it extending beyond the usual 180-degree arc as sunlight beaming from behind Venus is scattered by the planet’s thick cloudy atmosphere.
When the air is transparent and seeing steady, amateur astronomers have photographed and observed the crescent wrapping a full 360 degrees around the planet’s disk – a sight quite unlike anything else in the sky.
In the coming week, watch for Venus starting about 15 minutes after sunset low in the southwestern sky. With each day, the planet becomes slightly less conspicuous as it competes against the twilight glow.
After final farewells late next week, we’ll look forward in the new year to welcoming the goddess in her new guise as morning star.