Astronomy Picture of the Day

Explanation: What phase of the Moon is 3.14 radiansfrom the Sun?The Full Moon, of course.Even though theMoon might look fullfor several days, the Moon is truly at its full phase when it isPi radians(aka 180 degrees) from the Sun inecliptic longitude.That's opposite the Sun in planet Earth's sky.Rising as the Sun set on March 9, 2020, only an hour or so after themoment of its full phase, this orange tinted andslightly flattenedMoon still looked full.It was photographed opposite the setting Sun from Teide National Parkon the Canary Island of Tenerife.Also opposite the setting Sun, seen from near the Teide volcano peakabout 3,500 meters above sea level, is the mountain's risingtriangular shadowextending into Earth's dense atmosphere.Below the distant ridge line on the left are thewhite telescope domes ofTeide Observatory.Today, March 14 2025, the moon isPi radians from the Sun at exactly 06:55 UTC.That's about three minutes before the midpoint of the March Full Moon'stotal lunar eclipse.