Stargazers, ready your telescopes: An unusual lunar event is going to be visible across large portions of the U.S.
It's called an "occultation," in which the waning gibbous moon will pass over the huge, bright orange star of Aldebaran. We thought the phenomenon's spooky name might be just the thing to get geared up for Halloween.
The event will be visible across large portions of the South and the Northeastern United States, Mexico, the Caribbean and parts of Canada. "The most interesting views will be from a strip of land only a few hundred yards wide along the occultation's northern limit," where a "grazing occultation" will be visible, according to the International Occultation Timing Association.
That's where the Aldebaran star — which is the bull's fiery eye in the Taurus constellation — will appear to graze the top edge of the moon. "Viewed from the narrow graze zone, the giant star should disappear and reappear multiple times as hills and valleys along the Moon's northern limb cover and expose it," the IOTA adds.
The area where the grazing occultation is visible passes through or near many highly populated areas, including Los Angeles, Las Vegas, Denver, Minneapolis and Sioux Falls, S.D. Sky & Telescope has this handy map showing where the occultation is visible and where the graze line is:
Head here for a detailed list of the exact moment to catch the occultation at more than 1,000 locations.
Here's more on what to expect tonight from Space.com:
"The star will disappear on the moon's bright side and reappear on the dark side.
"As the moon, three days past full, ascends the eastern sky, Aldebaran will appear to creep up to the moon's bright limb for many minutes, then hang on the sunlit edge of a few seconds — an eerie orange fire among the lunar hills. You'll need a telescope to see it there through the moon's glare. Then, in an instant, it will snap out of view.
"Aldebaran will reappear from behind the moon's dark portion (depending on your location) up to 75 minutes later. This time you may be able to see the event with binoculars, since the star will pop back into view farther away from the dazzling lunar surface."
If you're having trouble seeing Aldebaran, EarthSky says that covering the moon with your finger could help.
Aldebaran is gigantic — according to EarthSky, if it was "placed where the sun is now, its surface would extend almost to the orbit of Mercury." It's also "about 153 times brighter than the sun." Fun fact: EarthSky says "Aldebaran is the name of one of the chariot horses in the movie Ben Hur."
"These occultations of Aldebaran have been happening once per lunar month in a series that began in January 2015 and will end in September 2018. But most aren't visible in the U.S.," as USA Today explains. "After this series ends, the next occultation of Aldebaran won't be until 2033."