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The Gang’s All Here

The return of Venus and Mercury brings us a chance to see all five naked-eye planets

A day past full, Thursday’s moon rises as the sun sets. The bright light to its upper right is Procyon, of the constellation Canis Minor. Higher still is golden Jupiter, the brightest object in the evening sky aside from the sun and moon. A couple nights later on the 18th, the waning gibbous moon rises a few hours after sunset in the company of Regulus, the heart of Leo the lion. Regulus is the bottom point in the Sickle of Leo, a grouping of stars that looks like an inversed question mark.
    By the beginning of the week, the moon is rising after midnight. Look for it before dawn Wednesday with Mars and Spica to the left. Mars is the brighter of the two, and its ruddy hue is in contrast to Spica’s cool blue-white glow. Before dawn Thursday the 23rd, the moon pulls within one degree of Spica with Mars barely five degrees above the pair. While Spica is the brightest star in the constellation Virgo, with the glaring moon so close you may want binoculars to spot it.
    Saturn trails Mars by roughly 20 degrees, rising around 3am and fairly high in the southeast by dawn. Observed with a telescope, Saturn’s rings are obvious tilted 22 degrees toward us, and they more than double the planet’s apparent size.
    With the approach of dawn, look to the southeast for Venus, which is emerging from the glare of the sun and beginning its apparition as the Morning Star. Right now Venus is fast pursued by the sun, visible for less than half an hour and climbing less than 10 degrees above the horizon before daybreak. Even so, our sister planet blazes at magnitude –4.3, brighter than any planet or star. Seen through a telescope, Venus is huge but thin, showing only a sliver of its face.
    Venus isn’t the only planet returning to view. By Sunday, Mercury appears just after sunset in one of its two best evening apparitions of the year. You’ll need a clear view to the point of sunset if you want to spot the innermost planet, and binoculars will definitely help pick it out from the glare of the horizon. Traveling so close to the sun, Mercury is elusive, so don’t give up if you don’t spot it at first. Through January the planet will distance itself from the sun, appearing higher and longer night by night. By the 31st, Mercury will set more than 90 minutes after the sun.
    You won’t have to hunt to find the fifth naked-eye planet this week, as Jupiter is visible pretty much from dusk to dawn. It’s the brilliant light low in the east at sunset, many times brighter than the nearby stars Castor and Pollux in the constellation Gemini. By midnight Old Jove is almost directly overhead.