How to Watch Tonight's Penumbral Lunar Eclipse and Comet 45P

Flickr / MarkGregory007

If you haven’t heard of a penumbral lunar eclipse, now’s the time to learn. Because on Friday night, February 10, North Americans will have a front-row seat for the penumbral lunar eclipse, which is different than a total lunar eclipse. Instead of the sun, Earth, and moon aligning perfectly, a penumbral eclipse involves the moon passing through the outer part of Earth’s shadow, so only a small sliver of sunlight bounces off.

The eclipse lasts for about four and a half hours and will occur in the early evening hours if you’re on the East Coast. The best time to watch will be between 7 p.m. and 8:30 p.m. Eastern. The peak of the effect will be around 7:45 p.m. when the moon is almost fully immersed in the penumbra shadow.

The moon will be blocked by Earth's outer shadow, the penumbra.

Earth’s shadow has two dimensions: the umbra and the penumbra. The umbra is the stronger, denser shadow, which blocks the moon entirely during a total eclipse, offering up a few moments of complete darkness. But, the penumbra shadow is very faint, so the moon will simply just look dimmer.

No special equipment is needed to see the show, just look toward the eastern sky and watch as the moon becomes duskier. It should be easy to see as Friday night is also a full moon, known as the “Snow Moon.”

Penumbrals occur two to four times a year, making them fairly common for our celestial calendar. Total lunar eclipses are much rarer, and the next one won’t be until January 2018.

Comet 45P/Honda-Mrkos-Pajdusakova will make a close pass traveling at 22.91 km/second, to the Earth-Moon system, at 3:23 a.m. Eastern time.Flickr / blobrana2

If you stay up late enough on Friday, you can look to the Western sky for Comet 45P/Honda–Mrkos–Pajdušáková, which streaks by around 3 a.m. Eastern. If you happen to be up, know that it will be a pale green color (from its fluorescent carbon gas).

“You will need an extremely dark sky and optical aid (at least binoculars, probably a telescope) to see this comet,” advises Deborah Byrd of EarthSky about Comet 45P.

So, if you’re looking for a change of pace this Friday night, ditch the TV and watch the night sky. If you can’t make it outside, watch the “Full Snow Moon Eclipse” broadcast.