That “Old Man River” will this week become that “Old Moon River” as the Mississippi divides the U.S. into lunar haves and have-nots.
In the early hours of Wednesday, May 26, 2021 a total lunar eclipse in the constellation of Scorpius—also known as a “Blood Moon—will be visible in North America for the first time in nearly two and a half years.
It’s set to be a rare lunar trifecta—a “supermoon,” a “blood Moon” and a full Moon all rolled into one event—but what you see will depend entirely on where you are on the continent.
Here’s a global map of visibility—as you can see, it’s the Pacific Rim that get the best views:
Let’s break down exactly what the three headline events are, and who will see them:
- Full Moon (for everyone on the planet): May’s “Flower Moon” will rise as normal, and be best viewed at moonrise in the eastern sky around dusk on May 25, 2021.
- Supermoon (for everyone on the planet): the full Moon appear about 7% larger than average because the Moon will be at its closest to Earth on its monthly elliptical orbit. It’s therefore going to be the biggest and brightest full Moon of the year.
- “Blood Moon” total lunar eclipse (only for the western U.S. and Canada, all of Mexico, most of Central America and Equador, western Peru, southern Chile and Argentina, eastern Australia, New Zealand, and the Pacific Islands, including Hawaii): the full Moon will drift into Earth’s central shadow in space at 11:18:40 UTC and turn red for 15 minutes—lunar totality.
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Here’s exactly what the “Blood Moon” will look like at the moment of totality, according to NASA:
So what has the Mississippi got to do with any of that?
Well, the U.S. is on the border zone of visibility for the all-important (though brief) totality of this lunar eclipse.
Those west of the Mississippi will see totality while those east of the Mississippi will not.
Totality can be seen everywhere in the Pacific and Mountain time zones, along with Texas, Oklahoma, western Kansas, Hawaii and Alaska, as this map from NASA shows:
Meanwhile, the start of the partial phase will be seen everywhere (including Puerto Rico) except eastern Pennsylvania, eastern Delaware, New York east of Buffalo, and the rest of New England:
Let’s unpick that.
The three different stages of a total lunar eclipse
- Penumbral eclipse (a dulled full Moon in Earth’s outer penumbral shadow).
- Partial eclipse (the Moon begins to turn red as it enters Earth’s inner umbral shadow).
- Total eclipse (the whole of the Moon is red while within that umbra).
Within the U.S. Lower 48, those in the Pacific time zone will get the best view of the entire event, peaking with lunar totality.
So here’s a diagram of the event with times in PDT:
However, the supermoon—in either a penumbral or partial eclipse—will be visible across the U.S. Those east of the Mississippi River will see a partial eclipse, but no totality—and the closer to the Mississippi to the more the full Moon will turn red as it gets close to setting.
Put your location into this page and you’ll get a full schedule of exactly what you’ll see from where you are, and when.
Is it worth seeing a penumbral lunar eclipse?
If all you’ll see is the penumbral eclipse (as will be visible on the east coast), don’t get too excited because the Moon’s appearance won’t be much affected.
You’re better off treating this event as the biggest and brightest full Moon of the year, and making a plan to watch it rise in the east at dusk on May 25.
Why you should look at the partial lunar eclipse
If you’re in a zone where you’ll see some of the partial eclipse, do get up early on May 26 and have a look; in the western sky the full Moon will look bright grey on one side and a copper red color on the other. T
hat line between the two is a projection of Earth’s shadow in space! It an odd sight indeed.
Why you must look at the total lunar eclipse
An hour and a half after that the total phase begins for the western half of North America—and the full Moon will turn a ghostly copper color.
It will only last 15 minutes before the Moon begins to emerge from the central shadow, but boy will it will be worth watching!
Wishing you clear skies and wide eyes