Tonight – August 6, 2017 – the moon may look full and round in your sky. Yet this August full moon falls tomorrow, on August 7 at 18:11 UTC, which is during the daylight hours on August 7 for us in the Americas. Normally, it’s not vital whether the crest of the moon’s full phase falls in daylight or darkness for your part of the globe. The coming full moon is a bit different, however, because it will undergo a shallow partial lunar eclipse. We in the Americas will miss it because the full moon crests in daylight, for us. And a full moon is always opposite the sun, up all night. Thus the moon will be below our horizon when the eclipse takes place.
In North America, we often call the August full moon the Sturgeon Moon, Green Corn Moon or Grain Moon. Hence the cool image at top by Hope Carter Photography; it’s an August full moon and ripening corn in her home state of Michigan. Click here for full-sized image.
At U.S. time zones, full moon comes on August 7 at 2:11 p.m. EDT, 1:11 p.m. CDT, 12:11 p.m. MDT and 11:11 a.m. PDT.
You have to be in our world’s Eastern Hemisphere to see this month’s moon when it’s precisely full. People on that half of the globe will see the partial eclipse on the night of August 7-8, 2017. Read more about the August, 2017 partial lunar eclipse.
Technically speaking, the moon is full for a only fleeting instant – when the moon is 180o from the sun in ecliptic longitude. The worldwide map below shows you the day and night sides of the world at the instant of the August 7 full moon.
You have to be on the nighttime side of the world to see the moon at the exact instant that it turns full. If the moon turns full during the daylight hours – as this August 2017 moon does in North and South America – then the moon is below your horizon.
Astronomically speaking, we in North and South America will be watching an almost-full waxing gibbous moon on the night of August 6-7 and an almost-full waning gibbous moon on the night of August 7-8.
Everyone around the word, however, will see a full-looking moon in the east at dusk or nightfall on August 6 and 7, highest up for the night around midnight and sitting low in the west at dawn. The moon stays more or less opposite the sun for the duration of the night after darkness falls for these next few days.
Bottom line: In North America, we sometimes call the August full moon the Sturgeon Moon. Watch it light up the nighttime from dusk August 6 until dawn August 7, 2017.
Bruce McClure has served as lead writer for EarthSky's popular Tonight pages since 2004. He's a sundial aficionado, whose love for the heavens has taken him to Lake Titicaca in Bolivia and sailing in the North Atlantic, where he earned his celestial navigation certificate through the School of Ocean Sailing and Navigation. He also writes and hosts public astronomy programs and planetarium programs in and around his home in upstate New York.