Whenever the full Moon is in the sky, many kinds of astronomical observation must be postponed. But a special treat is in store on Monday the 12th into the morning hours of Tuesday, the 13th. Across the United States (excluding Alaska), as well as southern and eastern sections of Canada during these overnight hours, observers can watch the Moon pass in front of the bright star Aldebaran. Aldebaran is the angry orange eye of the bull in the constellation Taurus, and is the 13th brightest and most colorful in the night sky.
Actually, to be more precise, this will not be a “full” Moon; but it will be less than one day before full and 99 percent illuminated. For the western U.S, this is an early evening event; for the eastern U.S. it happens around the middle of the night (if you live in New York, for example, the disappearance will occur at 4:13 a.m. EST with a reappearance at 5:27 a.m. EST). Aldebaran will appear to move toward the bright eastern (left) limb of the Moon. High magnification through a good telescope should give the best view of Aldebaran in the final few seconds before it suddenly winks out of sight behind the slight phase defect of darkness. About an hour later the star will reappear just as suddenly on the opposite side of Moon’s disk.