Five Easy Pieces

As the sky grows dark, the first light you’re likely to spot is Jupiter high in the west, slipping toward the horizon and setting around midnight. Above it are Pollux and Castor, the two brightest stars in the constellation Gemini. Orange-hued Pollux is the 17th brightest star, and white-hot Castor is the 23rd brightest. But at magnitude –2, Old Jove is exponentially brighter.
    Mars is another easy target, appearing high in the south at dark and setting in the west around 3:30am. While it is no brighter than a strong star, its steady red glow stands out among the stars.
    You’ll have to hunt for Mercury amid the ashen light of sunset, when the innermost planet hovers within 10 degrees of the west-northwest horizon. Mercury reaches its farthest point from the sun on the 25th, when it appears 15 degrees above our horizon at sunset and remains visible for almost two hours. These next couple weeks are the best chance all year to see this elusive planet at night. On Tuesday and Wednesday nights look for Mercury between the two stars that mark the horns of Taurus the bull.
    As Mercury sinks toward the northwest horizon, Saturn rises in the southeast. The ringed planet is also making its best nighttime appearance of the year and shines overhead from dusk until dawn. Below it snakes the form of Scorpius punctuated by red-glowing Antares.
    Venus is brilliant as the Morning Star low in the east at dawn. It rises around 5am, and as daybreak nears it blazes from its perch 15 degrees above the horizon. Keep an eye on its leisurely climb and you can spot it shining through the glare of early morning.
    Another bright light pierces the darkness this week, as the International Space Station makes several good appearances. At its dimmest, the ISS rivals any star; at its peak, it can rival Venus. But while the stars and planets give you time to pause, the space station streaks by in a matter of minutes. Traveling 17,000 miles an hour, it orbits the earth every 90 minutes. Unlike the lights from a passing airplane, you aren’t seeing the lights aboard the ISS. Instead, hovering 250 miles over the planet, the station receives plenty of sunlight, which is reflected back to our eyes.
    Friday morning the ISS appears in the southwest at 5:16am, climbing toward the celestia zenith, then disappearing in the northeast at 5:20. Saturday it appears almost 30 degrees above the south-southwest horizon at 4:30am, climbs another 30 degrees, then vanishes three minutes later in the east-northeast. Tuesday the station appears almost directly overhead at 3:42am and shoots to the north before disappearing two minutes later. For more detailed sighting opportunities, visit http://spotthestation.nasa.gov.