Early Wednesday, for the first time in 152 years, Americans will witness a rare trifecta of lunar activities: a super blue blood moon. This is when three unique lunar events occur: a super moon, a blue moon, and a blood moon. But it won’t be a goodnight moon or a midday event like a total eclipse—it’ll actually occur in the morning, beginning a little before 6 a.m. on the east coast.
What’s a Super Moon?
If “super moon” sounds familiar, that’s because one just occurred before the New Year. What earns this full moon the “super” moniker is a coincidence that goes back to the moon’s orbit around the Earth. Depending on when a moon is in its orbit, a full moon can appear far away (the farthest point being the “apogee)”, or—in the case of the super moon that occurred both on December 3 and will occur again on Wednesday—at the point of the orbit closest to Earth.
While that might not seem like a big deal, the distance between the apogee and perigee is nearly 30,000 miles, or a distance that clocks in at longer than the distance of the Earth. Thanks to the fact that it’s winter right now (which means the Northern Hemisphere of the Earth is tilted more towards the Milky Way than during the summer, when it’s tilted away) the moon simply appears brighter.
What’s a Blue Moon?
Wednesday’s super moon is also a blue moon, which actually has very little to do with color. The moon certainly can appear blue at times, but anyone who’s looked up at the sky has also seen the moon appear golden, pinkish, orange, even red (the signifier of a blood moon—more on that in a bit). What actually makes this moon a “blue” one is the fact that it’s the second full moon in a calendar month. A lunar cycle is about 29.5 days, which means that in most cases, it’s safe to say that each month is going to have just one full moon. January, however, is a longer month, with 31 days; the most recent full moon was on January 1.
What’s a Blood Moon?
This full moon couldn’t stop at just being a super blue moon—it’s a blood moon, too, which is a specific type of lunar eclipse (this is where the color part comes in).
The fact that the moon shines in the sky isn’t because it’s a naturally glowing interstellar object, but the fact that it reflects the sun. The way we view the moon on Earth, however, is akin to wearing sunglasses: There’s a barrier to how we view the moon, and that barrier is the atmosphere, whose composition can alter how we see the moon. When the sun’s rays pass through the atmosphere, they undergo a process called Rayleigh scattering, where the more violet hues are filtered out but the more red hues come through.
During a blood moon, the moon lines up perfectly with the Earth and sun, but in a way that blocks out the sun, so that those reddish rays coming through from Rayleigh scattering tinge the moon a brilliant, fiery “blood” color. The sunlight is scattering and bending more than usual, causing the moon to appear red (and no, it's not the end of times).
How You Can See the Super Blue Blood Moon
The further west you are on the continental United States, the better.
Gordon Johnston, a program executive at NASA, told The New York Times that East Coasters will experience “penumbra”—the phase immediately before “umbra”, or when the Earth is blocking as much of the sun as possible and therefore making the moon as red as possible—at 5:51 a.m. ET, transitioning into umbra about an hour later, at 6:48 a.m. ET.
Midwesterners get to see more of it, with Johnston estimating that 6:15 a.m. CT and 6:30 a.m. CT will be the sweet spots.
Those in the Mountain time zone can see it from about 4:48 a.m. MT until about 7 a.m. MT.
West Coasters have it the best, with the show starting at 4:51 a.m. PT and not ending for more than an hour, around 6:05 a.m. PT.
How to Live Stream the Event
Not only do winter skies tend to be cloudy, but dawn’s presence around the corner from the umbra time, means sunlight could (ironically) get in the way of seeing the super blue blood moon. That and, if you’re on the East Coast, you really only have a few minutes to see the (literal) once-in-a-blue-moon event.
Here’s where technology comes to play. NASA will live stream the moon event from its public and moon-focused channels with coverage starting at 5:30 a.m. ET and lasting until about 11:30 a.m. EST. The Virtual Telescope will live stream as well.
NASA will also have a live stream from the Armstrong Flight Research Center off Edwards Air Force Base in the Mojave Desert.
The next total lunar eclipse will be viewable from North America next year, on January 21, 2019. Alas, that one will only be a super blue moon.