A Supermoon, Blue Moon, and Lunar Eclipse on January 31
Super Blue Blood Moon Eclipse
Heard about this “Super Blue Blood Moon” on January 31? Let’s break this down: That’s a Supermoon, a Blue Moon, and a Blood Moon on the same night, thanks to a total lunar eclipse. A convergence of all three events last happened 150 years ago. Find out the best places to see this event.
“Super Blue Blood Moon Eclipse” is the description many Web sites are giving for the full Moon coming up. So, what does this mean? A Moon that’s super-big? One that’s blue? One that’s blood red? Maybe a combination of blue and red! A purple Supermoon?
- A supermoon occurs when the Moon is closest to Earth during its orbit, and theoretically larger than average.
- A Blue Moon is the popular name for a second full Moon in the same calendar month.
- A”Blood Moon” refers to the Moon’s hue on the night of a total lunar eclipse; it normally turns a coppery red.
Put ‘em all together and that’s what you’ve got.
Actual astronomers smile and shake their heads at these catchy names. They really want more people to watch the sky, and having names for things helps with publicity.
Call it what you wish! Each celestial event is interesting in itself. When you put them together so they occur on the same night, it’s unique. Sometimes the celestial rhythms just sync up to make us wonder.
January 31 is also the grand finale of a trilogy of Supermoons that have been taking place since early December.
“Supermoon” is a new term. No one used it until a few years ago. Instead, the Moon’s closest approach to Earth—full or otherwise—was called a Perigean Moon. The problem is that even the very closest Moon does not look any larger than your average normal Full Moon. The size difference is too small for the naked eye to detect. But, okay, call it super.
A Moon at perigee can appear up to 14% bigger. January 31’s total lunar eclipse will occur 1.2 days after perigee so the Moon’s diameter will appear about 7% bigger than average. Image Credit: NASA/JPL-Caltech.
The “Supermoon” term has not been used merely for the closest Moon of the year, but also for the second closest, and third closest, and so on. This one coming up on January 31 is, for example, the third of a trilogy and the second closest of 2018. It’s 358,816 km away, as compared with the January 1 Full Moon which was 356,565 km away.
People post telephoto pictures on social media, depicting enormous-looking Moons in the sky. So astronomers like myself are concerned that the public will look up, see nothing unusual, and just shrug.
“Blue Moon” has become a popular term for the second Full Moon in a month; the name arose because of a Depression-era mistake in an astronomy magazine. The term was never used by astronomers or the ancient Greeks, or Native Americans, or anybody else. Despite the name, the Moon won’t look blue at all. Indeed, the expression “once in a Blue Moon” doesn’t apply since it’s not that rare; the event occurs every 2-½ years.
That said, the Total Eclipse of a Blue Moon hasn’t occurred since March 31, 1866. That’s 152 years ago!
Okay, what about Blood Moon? Well, a fully eclipsed Moon turns coppery orange. Actual blood is not copper-colored unless you have a serious hematological problem. But let’s not be picky. Blood is more dramatic than pennies, and there’s no reason not to call a totally eclipsed Moon a blood Moon even if this, too, is a very recently coined phrase.
Best Places to See Viewing Tips
First, note that this event is perfectly safe to view with the naked eye, unlike a solar eclipse.
Everyone in North American will witness the “Supermoon” and “Blue Moon” aspects. The “Blood Moon” color, however, is tricky because the Moon will set before it’s totally eclipsed in the entire eastern half of Canada and the U.S.
Live in the Pacific Time Zone? Those in Western states and Canadian provinces, Alaska, and the Hawaiian islands will have the best view of the coppery, totally eclipsed Moon. Look low in the west just before dawn. Its lowness will greatly deepen its ruddy hue. On Pacific Standard Time, the lunar eclipse begin at 3:48 a.m. PST. Totality will start around 4:51 a.m. PST and last until 6:05 a.m. PST. If you set your alarm, you can see the entire lunar eclipse, from start to finish.
Those further east will see a partial eclipse of the Full Moon—early morning before the Moon sets and morning twilight arrives.
If you live in the Eastern Time Zone, head outside about 6:45 a, EST. Look west-northwest and find an unobstructed view, ideally at a high point since the Moon is near the horizon at this time. At 6:48 a.m. EST, the darker part of Earth’s shadow will begin to blanket the moon and create the blood-red tint—and the Moon will set less than a half-hour later.
If you live in the Central Time Zone, head outside around 6:15 a.m. CST. Johnston said. The Moon will appear to be a blood-red color—and the view will remain until 7:00 a.m. CST, when the Sun rises.
In the Rocky Mountain region, the lunar eclipse will begin around 4:48 a.m. MST, as the darker part of Earth’s inner shadow blankets the Moon. Viewers in this area will see the eclipse peak around 6:30 a.m. MST until 7:00 a.m. MST, when the Moon will set.
Full Moon Names
With all these newly-hatched Full Moon names, let’s have some fun. The year’s lowest Full Moon has no official name. That’s the Full Moon closest to the June 21 summer solstice. Its low height makes it pass through extra air and usually gives it an amber hue. Let’s start calling it the “Honey Moon.”
If we keep repeating that term for the June Full Moon, maybe the media will pick it up and run with it. Let’s see if, five years from now, that becomes the established name for that Moon. Let’s all do it, and we can say we know how it started!
Whatever names you use, look at the Moon on January 31. We’re watching all of the Earth’s sunrises and sunsets at that moment reflected from the surface of the Moon.
About This Blog
Welcome to “This Week’s Amazing Sky,” the Almanac’s hub for everything stargazing and astronomy. Bob Berman, longtime and famous astronomer for The Old Farmer’s Almanac, will help bring alive the wonders of our universe. From the beautiful stars and planets to magical auroras and eclipses, he covers everything under the Sun (and Moon)! Bob, the world’s mostly widely read astronomer, also has a new weekly podcast, Astounding Universe!