Moon to Occult Aldebaran

Moon Occulting a Star

Astronomical alignments are special events, times when the motions of the Earth and the rest of the cosmos brings about a particularly interesting juxtaposition of objects in the sky. Today (Sunday 10 April) the waxing crescent Moon will align itself with the bright star Aldebaran, covering it completely for observers in various parts of North America. See this article from Sky & Telescope for a detailed overview of the cities and the exact timing for disappearance and reappearance of Aldebaran.

The Moon sweeps around the entire night sky and touches each constellation of the Zodiac every month, passing in front of hundreds of naked-eye visible stars during its journey. But it is very uncommon for the Moon to pass in front of the brightest stars in the night sky. Aldebaran is a 'first magnitude' star, one of only 22 stars that are at magnitude 1 or brighter (and only four of these are close enough to the Ecliptic to be ever occulted by the Moon: Aldebaran, Antares, Spica and Regulus)
. For that reason the covering and uncovering of a star like this is a dramatic event, worth taking a few minutes with binoculars or a telescope to watch the proper motion of the Moon as a vastly more distant star's light is interrupted by the surface on the edge of the Moon and the light twinkles and vanishes from view for an hour.

On the west coast, the event takes place in broad daylight, but that should not make it any less impressive. Disappearance is at 2:21 pm and reappearance at about 3:40 pm. Check the Sky & Telescope article for more precise timings from around North America.