Full Broken Snowshoe Moon Shines Tonight And Friday

Oil painting titled Indian Hunter on Snowshoes in the mid-1800s by Cornelius Krieghoff

There are many names for full moons, most of which trace back to Native American peoples and the early colonists. April’s full moon is traditionally known as the Full Pink Moon, named for the flower moss pink or ground phlox, which blooms across eastern North America in April. Other native tribes know it as the Sugarbushing Moon, Egg Moon, Frog Moon and Sprouting Grass Moon. Each names reflects a different seasonal event or tradition.

Here in the Lake Superior region where I live, the Anishinaabe (Ojibwe) people call an April moon the Broken Snowshoe Moon. Although I don’t know the origin of the name I suspect it refers to how a pair of snowshoes might end up after a long, brutal winter. We still have snow on the ground at my house, and if I were to head into the woods wearing mine, I’d scrape them up good.

The full moon rises tonight in Virgo about 6° (three fingers at arm’s length) to the upper left of Virgo’s brightest star, Spica and in line with Arcturus in Boötes. Stellarium

Whichever name you prefer, most full moons rise pinkish-orange because the thick atmosphere near the horizon scatters away the blue-violet end of the white light that reflects off the moon. Watching the moon rise from a location with an unobstructed horizon is still one of the best sights in the world. It’s even better when you can watch two full moons rise.

Yes, that’s right — we’ve got two full-moon nights to look forward to. At least if you’re a skywatcher in the Americas. Because the moment of greatest fullness (99.9 percent) happens at 6:12 a.m. Central Time Friday morning, we split the difference between tonight and tomorrow night. The moon will be about 99.7 percent illuminated tonight and 99 percent Friday evening. I doubt most of us will see the difference with the naked eye, but you might be able to tell in binoculars.

A full moon rises over Lake Superior in Duluth, Minn. Bob King

A full moon sits directly opposite the sun and faces it square on, the reason we see it all lit up. But wait. I just said that 99.9 percent would be visible at max full. What about that other tenth of a percent? The moon exactly faces the sun ONLY during a total lunar eclipse, when it forms a nearly perfect straight line with the sun and Earth. At other full moons, it’s slightly out of line, so a tiny fraction of the moon remains shaded — the .1 percent!

The moon’s 5° tilted orbit causes it pass above or below Earth’s shadow most of the time, the reason we don’t get eclipses every month and why we can’t see 100% of the full moon. NASA

In April, as in most months, the full moon passes a little above or below Earth’s shadow (and breaks the perfect lineup) because its orbit is tilted with respect to that of Earth’s orbit. If it orbited exactly in the same plane as Earth orbits the sun, we see a total lunar eclipse every month.

If you have good weather try to catch a moonrise the next couple nights. Click here to find moonrise times for where you live.