By Jason Samenow
On Monday evening at sunset, the waxing moon was 97.82 percent full as viewed from Ellicott City. ( Timothy Butz via Facebook )
Get ready for the full moon’s least prominent, most underwhelming showing of the year. Tonight’s full moon coincides with the most distant point in its orbit known as the apogee, which will make it appear smaller and duller than the typical full moon.
In fact, tonight’s lunar circumstances are exactly opposite of the Supermoon - which we experienced May 5. A Supermoon occurs when the moon is full on its closest approach to Earth, or at its perigee. Compared to the Supermoon, this apogee full moon should be about 14 percent smaller and 30 percent less bright. This so-called “beaver” full moon is 252,522 miles away from Earth compared to the Supermoon’s 221,822 mile approach - or roughly 30,000 miles more distant.
If you happen to be up early Wednesday morning (pre-sunrise) and not in the eastern U.S., for a short period of time the moon will appear even duller due to a penumbral lunar eclipse. During this kind of eclipse, the moon passes through the penumbral or outer part of the Earth’s shadow. As such, the Earth obscures parts of the sun, making the moon appear a bit duller. EarthSky describes the rather understated penumbral eclipse effect in more detail:
You won’t see a dark bite taken out of the moon by Earth’s shadow. And you won’t see the moon turn blood red as during a total eclipse of the moon. A penumbral eclipse is more subtle than either of these. At the central part of the eclipse, you’ll see a dusky shading covering about 90% of the moon’s face.