Marching with the Moon

The moon highlights some of winter’s best sights this week

The waxing moon brightens our evenings, reaching first-quarter Saturday when it joins the inconspicuous stars of Aries in the southern sky. Three stars outline the ram’s head: Hamal, the brightest, Sheratan and Mesarthim, the dimmest. Viewed through binoculars, which will help you spot these dim stars amid the moon’s glare, all three fit within the same field of view. Millennia ago, the sun passed through Aries at vernal equinox, which explains why such an obscure-shaped asterism became a major zodiacal constellation. Now, the sun is in the constellation Pisces when it hovers above the equator on March 21.

Sunday the moon shines just a few degrees west of the stars of the Pleiades cluster, which marks the shoulder of Taurus the bull. The next evening the moon appears east of the Pleiades. Without the moon’s added light, you can typically spot six of the mythological seven sisters of this cluster, but armed with binoculars you’ll see far more stars.

Monday the moon hovers above the red-giant Aldebaran, the eye of Taurus the bull. Trailing the Pleiades, Aldebaran is the 13th brightest star, its name Arabic for the follower. It sits within the Hyades cluster, a circle of stars that make up the bull’s face, but it is not part of the actual cluster, which is twice as far away at 150 light years.

By Wednesday, the moon shines near the center of the Great Winter Circle. Made up of Aldebaran, Orion’s Rigel, Canis Major’s Sirius, Canis Minor’s Procyon, Gemini’s Castor and Pollux and Auriga’s Capella, this grouping contains seven of the 25 brightest stars. Add in the red-giant Betelgeuse, marking Orion’s shoulder, and you have eight.

Early risers may notice the glow of Mercury low in the southeast about an hour before sunrise, a little after 7:15 this week.