Tonight – on March 4, 2017 – people around the world will see the rather wide waxing crescent moon shining close to Aldebaran, the brightest star in the constellation Taurus the Bull. From the United States, Mexico and the Caribbean, the moon more than comes close to Aldebaran. You can actually watch Aldebaran disappear behind the dark side of the moon and reappear on the moon’s illuminated side during the evening hours tonight. This event is called a lunar occultation of Aldebaran.
Whenever the moon travels through the constellation Taurus, it can swing anywhere from 5o south to 5o north of the ecliptic – Earth’s orbital plane projected onto the constellations of the zodiac. When the moon reaches a southern extreme, it occults – covers over – Aldebaran once every month for months on end. When the moon reaches a northern extreme, it then occults the stars of the Pleiades cluster for months on end. That’s because Aldebaran lodges to the south of the ecliptic, while the Pleiades star cluster resides to the north of it, as shown on the sky chart of Taurus below.
For the rest of this year, the moon will occult the star Aldebaran every month. The moon started this series of monthly occultations of Aldebaran on January 29, 2015, and the series will continue until September 3, 2018. To watch any one of these occultations of Aldebaran, you have to be at the right spot on the Earth’s surface. I’ll bet we’ll get some awesome photos, though, from EarthSky friends on Facebook and Google+.
This time around, the mainland United States and Mexico enjoy the prime spot for watching the lunar occultation of Aldebaran on the evening of March 4, 2017. The worldwide map below shows where the occultation takes place. Everyplace in between the solid white lines can see the occultation in the nighttime sky, on the evening of March 4, 2017. The short blue lines to the left of the solid white lines depict evening twilight. Click here for the occultation times for numerous Asian localities in Universal Time. Remember to convert Universal Time to your local time.
About seven and one-half years from now, the moon will reach a northern extreme in the constellation Taurus. At that juncture, the moon will occult Alcyone, brightest star in the Pleiades star cluster, for months on end. That’ll happen on a monthly basis from September 5, 2023 to July 7, 2029. Something to look forward to!
Bottom line: On the night of March 4, 2017, let the waxing moon show you the star Aldebaran, the brightest star in the constellation Taurus the Bull.