Have you ever looked up to the sky around sunset to see a crescent moon with the rest of the full moon partially visible? Your eyes are not deceiving you. In fact, one of history’s most famous artists and scientists, Leonardo di Vinci, gave the world the first explanation of how this natural phenomenon occurs. Because of his observations and explanations, this celestial wonder is now referred to by experts as the “Da Vinci glow.”
Your next chance to view the Da Vinci glow moon is this weekend, and we have the details on how to catch it, as well as some history you can impress your friends with.
According to NASA, the artist, thinker and scientist noticed the “ashen glow” of the full moon in a crescent moon and speculated that the residual light casting that dim glow was the earth, not the sun. He even made sketches in his notebook of the crescent moon with the glow. At the time, he believed light reflected off the Earth’s oceans and hit the moon’s oceans.
Da Vinci wasn’t exactly correct — the moon doesn’t have oceans — but considering his lack of ability to travel to the moon or access to modern scientific observation tools, he was pretty close.
Scientists now know the Da Vinci glow is a result of earthshine, or sunlight reflecting off the Earth’s continents and clouds. The light bounces back onto the moon’s surface and gives the unlit portion of the crescent moon a faint glow.
So, how can you see the Da Vinci glow moon this weekend?
LiveScience advises skywatchers to head outside and look toward the western sky in the hour after sunset from Sunday, May 21, through Tuesday, May 23. Most people should be able to see the glow with their naked eye. However, a pair of binoculars or a low-powered telescope will help you get an even better view.
This story originally appeared on Simplemost. Check out Simplemost for additional stories.