Did you see Venus and the moon last night? Tonight’s scene in the west after sunset isn’t as spectacular, but it’s still very beautiful. Around the world this Monday, September 9, the moon and the dazzling planet Venus pop out in the western sky almost immediately after sunset. As dusk deepens into night, watch for the planet Saturn and the fainter star Zubenelgenubi to come out above the planet Venus.
The waxing crescent moon shines more closely to Zubenelgenubi in the Americas than it does in Europe, Africa, Asia, Australia and New Zealand. In the world’s Eastern Hemisphere, the moon appears farther west of Zubenelgenubi – and more in the direction of Saturn.
But no matter where you reside worldwide, Zubenelgenubi appears highest up at nightfall, followed by Saturn and then Venus. As can be expected, Venus sets first after sunset, followed by Saturn and then Zubenelgenubi.
On the chart at the top of this post, we drew in the ecliptic – the pathway of the moon and planets. At present, Venus shines in front of the zodiacal constellation Virgo while Saturn is in front of the constellation Libra, fairly close to the Libra/Virgo border.
At northerly latitudes, the ecliptic hits the horizon at a shallow angle on September evenings. That means the waxing crescent moon, the planets Venus and Saturn, and the star Zubenelgenubi set sooner after sunset than they do in the Southern Hemisphere – where the ecliptic hits the horizon at a steep angle on September evenings.
From the Southern Hemisphere, it should even be easy to see the star Spica, the brightest star in the constellation Virgo. At northerly latitudes, Spica sits low in the glow of twilight, and sets before dark, so binoculars may be needed to spot this star below Venus from the Northern Hemisphere. Venus, the third-brightest heavenly body after the sun and moon, outshines Spica by about a hundred times.
If you have binoculars, double your fun by aiming them at Zubenelgenubi. You’ll see that this star is actually a double star. It’s probably a binary – two stars revolving around a common center of mass.
As this month marches toward October, Venus climbs away from the glow of sunset while Saturn falls toward it. Watch for Venus to pass by Saturn on the nights of September 19 and 20.
Bottom line: At dusk and early evening on September 9, 2013, the waxing crescent moon, the planets Saturn and Venus, and the star Zubenelgenubi can be found in the western sky.