Tonight – March 21, 2018 – the waxing crescent moon shines in front of the constellation Taurus the Bull and near its two most prominent signposts: the bright star Aldebaran and the Pleiades star cluster.
Look for these celestial gems at nightfall, in the vicinity of the moon. If you miss the sky scene tonight, try again tomorrow at nightfall, as the moon passes in font of the constellation Taurus the Bull over the next few days.
With the eye alone or binoculars, scan the dark side of the moon. You are might see the soft glow of earthshine illuminating the nighttime side of the lunar disk. Earthshine is twice-reflected sunlight – sunlight reflected from Earth to the moon, and then from the moon back to Earth.
As always, the moon travels eastward in front of the constellations of the zodiac at an average rate of about 13o per day or ½ degree per hour. For reference, your fist at an arm length approximates 10o of sky, and the moon’s diameter spans about ½ degree. Relative to the backdrop stars, the moon travels its own diameter eastward per hour.
On the sky chart below, you can see the moon’s change of position relative to Aldebaran from March 21 to March 23. The moon lies to the west of Aldebaran (in the direction of sunset) on the evening of March 21 yet to the east of Aldebaran on March 23.
The charts on this post are especially designed for North America. Nonetheless, from virtually everywhere worldwide, you’ll see the moon to the west of Aldebaran on March 21, and to the east of this star on March 23.
But as darkness falls in North America on March 22, 2018, the moon and Aldebaran will be quite close together on the great dome of sky.
From far-northeastern North America, it may be possible to witness the moon occult (cover over) Aldebaran at evening dusk on March 22. From Greenland, Iceland, and far northwestern Europe on March 22, the lunar occultation of Aldebaran occurs after dark.
Bottom line: Beginning March 21, 2018, watch the moon light up Taurus as it passes in front of the constellation of the Bull over the next several days.