Comet 45P/HMP passes by Earth at dawn tomorrow
If you find yourself up at dawn tomorrow, go ahead and look up into the dawn sky. Who knows? You might just catch a glimpse of Comet 45P/Honda-Mrkos-Pajdusakova swinging past Earth on its way back to the outer solar system.
Discovered in 1948, Comet 45P/HMP is a middle-aged dwarf comet with a nucleus that is roughly half a mile across. Its orbit takes it past the Earth every five years or so.
(In case, you, like me, need help spotting specific constellations in the night sky, check out 15 Constellations Every Man Should Know (And How to Find Them) on The Art of Manliness Blog. There are smartphone apps for spotting constellations, too, of course. We here at Caterpickles Central are partial to Star Walk.)
Don’t feel like getting up at Stupid O’Clock*? That’s ok, there’s a penumbral lunar eclipse tonight.
Starting at 6:14 p.m. EST this evening, sharp-eyed sky watchers in the Americas will be treated to a penumbral lunar eclipse. The views will be best in the eastern portion of North America, as well as Central and South America, but even us Midwesterners might be able to catch a glimpse of the action before the eclipse ends. Maximum shading of the moon is projected to happen at 7:44 p.m. EST.
What’s the difference between a penumbral eclipse and a total lunar eclipse?
Tonight’s eclipse is what’s called a penumbral eclipse, not a total lunar eclipse. The moon won’t turn red, but will simply be dimmer than usual. That’s because in tonight’s eclipse, the moon is only passing through the penumbral shadow (the edge of the Earth’s shadow), and the light from the sun will only be partially blocked.
In a total lunar eclipse, the moon passes through the Earth’s umbral shadow. There, the Earth fully blocks the light from the sun. Indirect sunlight is still able to reach the moon, however, which is why the moon appears red in a total lunar eclipse, instead of going fully dark.
For more on the various types of lunar eclipses, check out this handy guide for beginners on MrEclipse.com.
* Thanks to The Nine-Year-Old’s Uncle Phil for the phrase, Stupid O’Clock, hands-down our favorite way to refer to the painfully early morning hours.
- Top 7 Must-See Sky Events for 2017 (National Geographic)
- Lunar Eclipse and 10 More Can’t Miss Sky Events in February (National Geographic)
- Lunar Eclipses for Beginners (Mr. Eclipse)