Following last week’s conjunction between Regulus and Mars, the moon now gets in on the act. This meeting of a star, a planet and a moon takes place on 29 June. The chart shows the view looking west from London at 22:15 BST that day.
Red planet Mars has moved on from its close pass of blue-white star Regulus, giving enough space for a waxing crescent moon to slip in between them. The moon will be 4.7 days old, and heading towards its first quarter (half-moon) phase. Just over 22% of its visible surface will be illuminated.
From the moon, our nearest celestial neighbour, it takes the sunlight that bounces from its surface just 1.3 seconds to reach our eyes. For Mars, the fourth planet in our solar system, the light travel time from its surface is 15 minutes and 57 seconds. And for Regulus it takes light 79 years to reach us. So we see the moon as it appeared 1.3 seconds ago, Mars as it appeared 15 minutes and 57 seconds ago, and Regulus as it appeared 79 years ago.
The conjunction is easily visible from the southern hemisphere too, where it will appear in the north-north-west.