Three Planets Will Slide Behind the Moon in an Occultation.
'At the start of this week, the moon will play a game of planetary peek-a-boo as it momentarily blocks Venus, then Mars and then Mercury in the sky. Although it will be difficult to see this disappearing act in much of the world, it’s a vivid reminder of the cosmic clockwork at play in our solar system.
The event is called a lunar occultation, and it occurs whenever the moon passes in front of a faraway celestial object. The duration of a lunar occultation depends on many factors, like what is getting blocked and where on Earth someone is observing it from. Solar eclipses, like the one that mesmerized the nation last month, are examples of the moon occulting the sun (but with far more risk to your eyes).
When you’re in the right place, with the right viewing equipment, lunar occultations can be quite breathtaking, like the one that occurred in 2007 when the moon occulted Saturn.
The last time the moon slid past three planets within 24 hours as it will this week was on March 5, 2008 (when it was Mercury, Venus and Neptune), and the next time will be in 2036, according to EarthSky. During this year’s event, as a bonus, the moon will also interrupt the light from Regulus, the brightest star in the constellation Leo, a few hours after it passes Venus.
“It’s almost like it’s a dance in the sky,” said Jackie Faherty, an astrophysicist at the American Museum of Natural History. “It’s going to pass its partners.”
According to Universe Today, the lunar occultation will occur during hours from Sunday evening through Monday evening in the Eastern time zone.'>>>
https://www.nytimes.com/2017/09/17/science/occultation-moon-mars-venus-mercury.html?