A rare celestial event is about to occur this weekend, as the waxing crescent moon lines up with Mars and the bright star Regulus above the western horizon. For some lucky viewers, the moon will pass directly in front of Mars, blocking its view.
On Saturday (June 28), just after sunset, the crescent moon will be visible roughly 20 degrees above the western horizon. As dusk turns to night, the trio of Mars, Regulus, and the moon will align to the upper left of the lunar disk. The next three hours will bring a brief, spectacular moment when the moon slips out of view.
The following night, Sunday (June 29), the waxing moon will jump to the lower right of Mars, creating an impressive sight as it appears to sweep underneath the Red Planet. This event is known as an “occultation,” and some viewers will witness the moon pass directly in front of Mars.
This phenomenon is only possible because of the moon’s relative proximity to Earth, which can shift its position by around 2 degrees depending on the viewer’s location. The lunar occultation of Mars will be visible from parts of Peru, Ecuador, Colombia, and Clipperton Island in the hours following June 29 at 6:57 p.m. EDT (22:57 GMT).
Astronomers can make the most of this event with a quality telescope or binoculars. For beginners looking for reliable views, the Celestron NexStar 4SE is an ideal choice.
Source: https://www.space.com/stargazing/see-the-crescent-moon-dance-with-mars-and-the-bright-star-regulus-this-weekend