I woke up about 4:30 this morning with the moon shining through my window. I hadn’t expected to see it as it had been cloudy when I went to bed. This was an important full moon for several reasons. First there was a partial penumbral eclipse and second, it was the smallest full moon of the year.
This full moon is called the Beaver moon by some native Americans and is also known as the Frosty moon. This from the Washington Post
The U.S. Naval Observatory’s Geoff Chester offers the reasoning behind the name: “[The] name comes from Native American skylore reminding trappers to set their final traps for the season before the beaver ponds freeze up for the winter,” Chester writes.
Chester notes this moon is sometimes also referred to as the “Frosty Moon.”
So what is a penumbral eclipse anyway? EarthSky explains
What can you expect to see during the November 28, 2012 penumbral lunar eclipse? First, here’s what you will not see. 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. By the way, that brilliant planet near tonight’s moon is the king planet Jupiter. The moon and Jupiter will be even closer together tomorrow night.
So, before you set your alarm clocks, consider yourself forewarned. A penumbral lunar eclipse is not nearly as stark and obvious as an umbral eclipse of the moon. During an umbral lunar eclipse, the moon passes through the umbra– the Earth’s dark, cone-shaped shadow. During a penumbral eclipse, the moon passes through the light penumbral shadow surrounding the umbra. (See feature diagram at top.) Your best chance of noticing any penumbral shadow on the moon’s surface is at mid-eclipse (greatest eclipse) in a dark sky not obscured by dusk or dawn.
But the eclipse was not visible in Boston so all I saw was the smallest full moon of the year. This was the smallest and least bright because the moon was at apogee or at the furthest point from the earth. It might have been the smallest and least bright but it was still enough to wake me up.
This photograph is by Duke Marsh and was posted on EarthSky today. The little dot at 10 o’clock is Jupiter.