There will be a penumbral lunar eclipse Friday. What’s that?
After Thursday’s snowstorm, it’s nice to be writing about an astronomical, not meteorological, event.
The weather pattern has turned active with two more storms possible in the next week, but it appears as if we will have a window of clear skies Friday evening long enough to enjoy a celestial event.
Friday evening the moon is going to pass within the penumbra of the Earth’s shadow. This shouldn’t be confused with the umbra, which is the shadow itself. The penumbra is the dusky part of the Earth’s shadow, before you get to the shadow itself. When there is a full lunar eclipse, the moon passes through the Earth’s shadow and disappears.
The penumbra is the dusky part of the Earth’s shadow.
It’s difficult to have a penumbral eclipse because the sun, Earth, and moon must be aligned imperfectly. If the line-up were exact, we’d have a full lunar eclipse.
On Friday, the moon will miss the Earth’s full shadow by only about 100 miles. The entire moon will also almost be inside the penumbra. The top of the moon, closest to the full shadow, will show the best color.
These events move in slow motion. This one will last four and a half hours, and the best viewing time will be at roughly 7:44 p.m. If there are any clouds, even high ones, it will make the subtleness of this event more difficult to view.
A penumbral eclipse is more subtle than a full lunar one.
Comet 45P also visible
If we do have clear skies Friday, you might be able to see Comet 45P/HMP when it makes its closest pass to Earth this weekend. This isn’t an easy thing to spot: You will need a telescope or binoculars. You might want to check with a local planetarium to see if they are offering any tours to help spot this comet.
Looking east a couple of hours after sunset on a clear night, you can also spot the constellation Leo.
The full moon alongside Leo the weekend.
