Utah Skies: Crescent Moon Meets Three Planets

May 24, 2021

Credit Tom Westre

As the moon orbits Earth we see the different phases it goes through during the month. From the new moon to the full moon the illuminated crescent grows in size each day, this is called a waxing moon. From full moon to new moon the illuminated area grows smaller and is known as a waning moon.

The waxing phase begins with the new moon. The lunar disk is not visible to the unaided eye as the moon in its orbit around the Earth lies between the Earth and the Sun. The moon’s near side is dark from an observer on the Earth, while the side facing away from the earth is illuminated.

As the Moon continues to orbit the Earth more and more of the earth facing side is illuminated or it waxes until it reaches full moon.

This month the new moon begins May 11. For the next three nights, the waxing moon puts on a lunar and planetary show in the evening after the sunsets. 

Wednesday the new crescent moon will be just to the lower left of the planet Venus right after the sun sets. A pair of binoculars will help in viewing the pair. Venus is now the Evening Star and will remain in the Western sky for the next few months. 

 Thursday the crescent moon will be to the left of the planet Mercury. The pair will be easy to see as they set about 10 p.m. A pair of binoculars will show them together and Venus nearby. 

Saturday the waxing moon has now moved so it lies just below the planet Mars. As you view Mars don’t forget about the NASA Mars rover Perseverance that is successfully sending back images from the Martian surface.

As we move into May the warmer weather provides a great opportunity to enjoy the evening show of the waxing moon as well as Venus, Mercury, and Mars.