The sky presents two lunar spectacles for the price of one tonight. The full “Hunter” moon rises, while at the same time, sections of it are darkened by the outer part of the Earth’s shadow, an event known as a penumbral eclipse.
In Washington, D.C., the moon rises at 6:14 p.m. this evening, and, by then, the eclipse will have already begun (it officially begins at 5:51 p.m. EDT). It will be most noticeable around 7:50 p.m., the time of maximum eclipse, says Geoff Chester of the U.S. Naval Observatory.
“At this time you should notice a distinct darkening of the bottom of Luna’s disc,” writes Chester. “The shading will be quite subtle, but it should be readily apparent when compared to the northern limb. The darkening will then slowly shift to the southwestern limb before the eclipse ends at 9:52 pm.”
EarthSky emphasizes the subtle aspect of the eclipse because, coinciding with evening twilight in the U.S., the sky will not yet be that dark.
“You may not notice any shading at all on the moon’s surface if you see the eclipse from the Americas,” Earth Sky writes. “Even as the eclipse is happening, you’ll be seeing the moon low in the sky, peering at it through more atmosphere than when the moon is overhead. This is a very, very subtle kind of eclipse. Will it be noticeable? Maybe to photographers! We’ll hope for some good photos.”
It adds: “Europe and Africa will be in a better position to see the subtle penumbral eclipse because the lunar eclipse takes place at late night (instead of evening or morning twilight).”
Whether or not the eclipse, the last of 2013, stands out, the moon itself will be striking, reaching 100 percent fullness at 7:38 p.m. EDT.
“Native Americans named this bright moon for obvious reasons,” writes the Farmers’ Almanac. “The leaves are falling from trees, the deer are fattened, and it’s time to begin storing up meat for the long winter ahead.”
Clear skies in the Mid-Atlantic and Northeast promise good moon viewing.