Around the Solar System
This week is your last chance of the year to spot all five naked-eye planets, although it’s not easy pickings against the light of Thursday’s full moon.
As darkness settles, look for Venus and Mercury low in the west-southwest. Venus shines so bright you may spot her even with the glare of the setting sun. Not so with Mercury. While the innermost planet is only two degrees below Venus, it is so tight against the horizon that it is best located with binoculars, at which point it is surprisingly bright. Thursday and Friday night, scan just below Mercury for the red glow of Antares, the setting heart of Scorpius. But don’t delay, as all these objects set within an hour of the sun.
Looking to the east at sunset, you should have no trouble spotting Jupiter, which rules the night skies, blazing far brighter than any neighboring star. At 11pm old Jove is high in the south, and come 5am he rests above the west horizon, setting a couple hours before the rising sun.
As Jupiter sets in the west, Saturn rises in the east. Don’t confuse the steady golden glow of the ringed planet with the equally bright flickering of blue-white Spica not five degrees below. With the approach of sunrise, around 6:45 this week, Saturn and Spica are still only 10 degrees above the horizon, but day after day the will rise a little earlier and climb a little higher before disappearing from sight.
If you can see both Jupiter and Saturn, look mid-way between the two for Mars, which
Mars rises around midnight and by 3am is well positioned in the east. Look just below the red planet for Regulus, the heart of Leo the lion. The two are close all week, but Friday and Saturday before dawn they are barely one degree apart.