A total lunar eclipse is a pretty cool event in its own right. Add in a blue moon and a super moon and you’ve got three celestial treats in one. Tomorrow morning we on the west coast may enjoy the first super blue blood moon visible in North America since 1866—if the weather cooperates.
A lunar eclipse isn’t all that rare. They can happen two or three times a year, but tomorrow’s will be the first visible (theoretically) from the Seattle area for a couple of years. The blue moon, under the generally accepted modern definition of the second full moon in a calendar month, isn’t quite so rare as the phrase “once in a blue moon” would suggest. On average, a blue moon happens once every 2.7 years. This year is a bit of an oddity, as not only will we have a blue moon tomorrow, but there will be another in March as well, and February has no full moon at all! Yes, there’s a name for that, too—black moon. And that’s also the name for a second new moon in a month.
Finally, the super moon—when full moon occurs near the perigee of the Moon’s orbit around Earth—happens about every 14 months, though we’re on a streak now; our December and early-January full moons were super as well. Blood moon is just a nickname for a lunar eclipse because the Moon often looks orange to deep red when totally eclipsed. None of these things, then, is unusual in and of itself, but getting them all to line up on the same day is quite a trick. The last super blue blood moon was 35 years ago (and I bet it wasn’t called that then), and the next won’t happen until 2037.
For the super blue blood moon on January 31, 2018, the penumbral eclipse begins just before 3 a.m., but this is subtle and difficult to spot even with telescopes or binoculars. The real show starts just before 4 a.m., when the darker part of Earth’s shadow, the umbra, begins to work its way across the face of the Moon. The Moon will be totally eclipsed at about 4:51 a.m., and will stay that way until 6:07 a.m. The umbral eclipse will end at 7:11, and the Moon will set about 7:45.
To see it—presuming it’s not cloudy—simply go outside and look west. The Moon will be fairly high in the sky at the start of this, but closer to the horizon towards the end.
Seattle Astronomy’s Greg Scheiderer talked about the eclipse on KING 5 television today with Margaret Larson on the station’s program New Day Northwest; video of the segment is attached below.
The Seattle Astronomical Society plans a viewing event at Solstice Park in West Seattle for those interested in a group experience. In the event of clouds, don’t despair; NASA will be live-streaming the eclipse, though that’s never as cool as the real thing.