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Close Encounters

Mars and Venus together at dusk

An ever-so-thin sliver of moon appears low in the west at evening twilight Thursday briefly before sinking beneath the horizon. The Evening Star Venus blazes above and to the moon’s left, with much fainter Mars just above Venus.
    Sunset Friday finds the two-day-old crescent moon within two degrees of Venus and Mars, all so close they easily fit within the eyepiece of binoculars and modest backyard telescopes.
    Come Saturday evening, the moon is roughly 10 degrees above Venus and Mars. But now the two planets are less than one-half degree of one another, with Mars just to Venus’s upper right. Venus shines more than 100 times as bright as Mars, so much so that its light could obscure the red planet, in which case you’ll need those binoculars to discern it. After that, Venus climbs higher into the west and away from Mars.
    While Venus and Mars appear together this week, the planets are actually millions of miles apart. Closer to the sun, Venus completes one orbit in roughly 225 days, while Mars makes the loop in 687 days. From our fixed vantage point here on earth — which isn’t really fixed, as we, too, are always in motion around the sun — these planets cross paths several times each year. But with roughly 75 million miles separating the orbital line of one planet from the other, there’s a lot of variance, so a close conjunction like this is pretty rare. Venus and Mars haven’t appeared so close in our sky since 2008, and they won’t again for another two years.
    Jupiter is a fixture of the night sky. It appears in the east as twilight fades, and by 11pm it is almost directly overhead. By 5am it is low in the west-northwest and sets just before sunrise.
    If you’re up before dawn, look for golden Saturn to the south. It is traveling with the constellation Scorpius, whose return to the skies each year heralds the coming of spring. The red heart of the scorpion, Antares, shines almost as bright as Saturn and less than 10 degrees below and to the left.
    The last of the naked-eye planets is just eeking away from the glare of the sun. Look for Mercury just above the east-southeast horizon in early dawn. Binoculars will help you pinpoint it against the glare of the coming sun.
    Wednesday’s first-quarter moon shines amid the constellation Taurus the bull and is less than one-half degree from its glaring red eye Aldebaran. Above the moon a little farther are the stars of the Hyades cluster, and higher still those of the Pleiades cluster.
    Some of the brightest stars appear during these cold, dark nights. Orion the hunter stands above the southern horizon in the evening, the three stars of his belt pointing up to Taurus and down toward Canis Major and the brightest star, Sirius. Orion’s foot is marked by Rigel, while his shoulder is the red giant Betelgeuse, with Canis Minor and its bright star Procyon to the left. Above these stand the Gemini Twins, Castor the higher and brighter star and Pollux a little below it. Above and to the right of Gemini is Capella, the bright star of Auriga the charioteer, shining directly overhead at 8pm. To the east is Leo the lion and its bright star Regulus.
    Just east of Orion is the winter Milky Way, stretching from the southeast to almost directly overhead and then down to the northwest in the early evening.