More than three years have passed since most of North America saw a good total lunar eclipse. So be sure to put a big circle on your calendar for Sunday, Jan. 20.
The viewing circumstances for the eclipse of the full moon that evening will be as good as they can get for much of the United States and Canada. The eastern side of the continent has the best view, but the spectacle of the moon completely immersed in Earth's shadow will be readily visible from coast to coast. The duration of totality will be longer than normal, too: It will last 1 hour and 2 minutes.
Moreover, coming as it does in early evening, the eclipse should arouse wide interest among the millions of people who can see it during normal waking hours. Amateur groups should take this opportunity to alert schools and news media about their eclipse activities and amateur astronomy in general. How about staging a neighborhood eclipse party? [Super Blood Moon Total Lunar Eclipse: Complete Guide]
A high moon ... and a huge audience
To describe a lunar eclipse, I like to use a movie theater analogy. The "theater," in this case, is the night side of Earth. The "screen" is the full moon, and the "movie" is the progression of Earth's shadow across the face of the moon.
Everyone in the theater looking at the movie sees the same thing everyone else around them is seeing. And, similarly, everyone on the night side of Earth who has the full moon in the sky during the eclipse will see the same sequence of events happening at the same moment in time.
The total phase of the eclipse will be visible from the Western Hemisphere, Europe and the western part of Africa, as well as the northernmost portions of Russia. In all, assuming good weather conditions, this shady little drama will have a potential viewing audience of some 2.8 billion people.
Of course, as is the case in a large theater, auditorium or concert hall, some will have a better view than others. For the upcoming eclipse, the "orchestra seats" will most definitely be in North America, which will see this celestial performance high in the midwinter sky. "Front row center" belongs to those who live near and along the U.S. East Coast, where the totally eclipsed moon will climb to extraordinary heights.
From New York City at midtotality, the darkened moon will stand 70 degrees up from the southern horizon — your clenched fist held at arm's length measures roughly 10 degrees in width, so that's "seven fists" from the horizon. The last time New Yorkers could gaze so high at a totally eclipsed moon was in 1797, when John Adams was president; the next opportunity won't come until 2113. Farther south, the moon will appear even higher. From Cape Hatteras, it will reach 75 degrees; Orlando, 80 degrees; and Miami, 83 degrees.
And from eastern Cuba, the moon will appear directly overhead.
Conversely, for those in Europe, the eclipse will take place low in the western sky as the moon approaches its setting at dawn on Monday, Jan. 21. In fact, for Central and Eastern Europe, the moon sets before it's entirely free of Earth's shadow.
Here is a complete timetable detailing the various stages of the eclipse for six different time zones:
|Moon enters penumbra||9:36 p.m.||8:36 p.m.||7:36 p.m.||6:36 p.m.||—||—|
|Moon enters umbra||10:34 p.m.||9:34 p.m.||8:34 p.m.||7:34 p.m.||6:34 p.m.||—|
|Total eclipse begins||11:41 p.m.||10:41 p.m.||9:41 p.m.||8:41 p.m.||7:41 p.m.||6:41 p.m.|
|Middle of eclipse||12:13 a.m.||11:13 p.m.||10:13 p.m.||9:13 p.m.||8:13 p.m.||7:13 p.m.|
|Total eclipse ends||12:43 a.m.||11:43 p.m.||10:43 p.m.||9:43 p.m.||8:43 p.m.||7:43 p.m.|
|Moon leaves umbra||1:51 a.m||12:51 a.m.||11:51 p.m.||10:51 p.m.||9:51 p.m.||8:51 p.m.|
|Moon leaves penumbra||2:48 a.m.||1:48 a.m.||12:48 a.m.||11:48 p.m.||10:48 p.m.||9:48 p.m.|
What truly makes this event "America's Eclipse" are two viewing criteria I have determined specifically for the contiguous (48) states:
1) The entire eclipse is visible from start to finish.
2) Totality begins before midnight from coast to coast.
In my more than 50 years of observing lunar eclipses, only two eclipses meet these criteria. One occurred in April 1968 and the other occurred on the very same date — Jan. 20 — 19 years ago. As one can see by examining the timetable, our upcoming eclipse also qualifies.
And it will be taking place on the Sunday night of the three-day Martin Luther King Jr. holiday weekend in the U.S. This will be the first time since 1975 that a total lunar eclipse coincides with a holiday weekend. With no school on Monday, kids of all ages should be able to stay up and watch this lunar show, no matter how late it is.
But what about Alaska and Hawaii?
Most of Alaska will see all stages of the eclipse unimpeded, but the eclipse will already be underway as the moon rises from the Aleutian Islands.
Similarly, observers in Hawaii should pay particular attention to the rising full moon early Sunday evening at around 6:10 p.m. Hawaiian time, for the eclipse will already be in progress. As the sun sets in the west-southwest, the moon will be coming up on the opposite side of the sky in the east-northeast; and Earth's umbra will already be covering the lower half of the moon's disk. An interesting observation to attempt is to try and see the partially eclipsed rising moon and the setting sun simultaneously. In a perfect syzygy alignment like this, such an observation would seem impossible; but thanks to our atmosphere, the images of both sun and moon are "lifted" above the horizon by atmospheric refraction. This allows us to see the sun for several extra minutes after it has actually set and the moon for several extra minutes before it actually rises. This situation is known as a "selenelion." The low, partially eclipsed moon in deep-blue tropical twilight should offer a wide variety of interesting scenic possibilities for both artists and photographers. [What Is a Lunar Eclipse? When and Why Blood Moons Occur]
For now, a short summation ...
When we get closer to the night of the eclipse, Space.com will provide an "observer's kit" for the eclipse and we'll go into much greater detail as to what to look for. But for the moment, I'll provide a more-or-less capsule summary as to what to expect.
The first listed event is the edge of the moon entering the penumbra, the pale outer portion of Earth's shadow. However, this event is completely unobservable. No change will be visible until about 25 minutes before the moon begins to enter the darker umbra. Around then, a slight shading should become detectable on the moon's east (left) side, which, as the minutes tick off, will appear to spread and deepen.
When the moon begins to enter the umbra, the change is dramatic. This part of Earth's shadow is much darker than the penumbra and fairly sharp-edged. As the umbra engulfs more of the moon, the eclipsed part will probably begin to glow with a deep-brown or ochre hue.
During totality, which will last 62 minutes, the moon will appear to glow like an eerie ball — which to the eye, and especially in binoculars and small telescopes — will appear almost three dimensional. The moon's color during the upcoming totality is not known. Some eclipses are such a dark, grey-black color that the moon nearly vanishes from view. During other eclipses, it can glow a bright orange.
The reason the moon can be seen at all when totally eclipsed is that sunlight is scattered and refracted around Earth by our atmosphere, and enough of this light reaches the moon to give it a faint, coppery glow even when it's totally eclipsed. Since the moon will be traveling through the northern part of Earth's shadow, the upper part of its disk will probably appear somewhat brighter than the lower part, because the upper part will lie closest to the outer edge of Earth's shadow.
Totality ends when the northeast (upper left) limb emerges from the umbra. Events now unfold in reverse order. The umbra's edge will take just over an hour to retreat across the moon's face. In another 25 minutes, the last of the penumbral shading should be gone, too, leaving the full moon at its normal brilliance.
Branding the eclipse
As one who has been involved with broadcast news for over four decades, I can tell you that the mainstream media is currently into what can best be described as a "branding craze." Terms such as "polar vortex" and "bomb cyclone" are two examples of words that newscasters now use when describing an impending spell of frigid weather or a rapidly intensifying storm, respectively. Broadcasting consultants advise news-gathering agencies to do this in order to draw instant attention to a story.
Now, with the lunar eclipse approaching, we find that it, too, has acquired a brand. Namely, the "Super Blood Wolf Moon" eclipse.
Traditionally, the January full moon is known as the "Wolf Moon." Names such as these are said to have been handed down from people living in old England or from Native Americans and are promulgated today in many popular almanacs, as well as here at Space.com. [Full Moon Names: From Wolf Moons to Cold Moons]
The term "Blood Moon" is at the very least a misnomer. Indeed, as I mentioned earlier, the color (or colors) that the moon will take on during totality will depend a lot on the state of our atmosphere and can run the gamut from black or gray to brown or red to even something resembling a bright copper penny. So to brand a lunar eclipse as appearing the color of blood is simply wrong.
I strongly suspect that the term came from a book that was published in 2013 by two Christian doomsday theorists who suggested that a series of total lunar eclipses in 2014 and 2015 signified disastrous portents. And what better way to suggest possible catastrophes than to invoke the mention of blood? How sad that in our 21st century world, there still lurk prophets of doom who promote a lunar eclipse — a life-enriching phenomenon — as a harbinger of some cataclysmic event.
PS ... The eclipses came and went, the supposed calamities never happened, but sadly the Blood Moon branding remains.
Not so "super" eclipse!
Sometimes, a full moon coincides with perigee — that point in the moon's orbit when it's closest to Earth — and will appear somewhat larger than usual. Traditionally, a full moon that occurs within 90 percent of the moon's perigee earns the title "supermoon." As it turns out, that's the very reason why this upcoming full moon is being referred to as a "super" moon. And the fact that it is coinciding with a total eclipse has the media agog with excitement.
But truthfully, a so-called "supermoon" is not really so great when it coincides with a total lunar eclipse. The duration of totality is based chiefly on the moon's distance from Earth. When the moon is near perigee, it is moving more rapidly in its orbit, compared to when it's near apogee, its farthest point from Earth; so it sweeps through the umbra more quickly.
In fact, if the moon were near apogee instead, I've determined that we would see up to 8 additional minutes of totality.
So get excited if you wish about the unusual closeness of the moon during this month's eclipse, and call it "super" if you want. But the bottom line is, when the moon is close, the amount of time that it is totally immersed in the umbra will be noticeably shortened compared to a moon farther out in space.
If only the mainstream media could tell it like it is and say simply that on Jan. 20, we will be treated to one of nature's great sky shows.
A total lunar eclipse!
Joe Rao serves as an instructor and guest lecturer at New York's Hayden Planetarium. He writes about astronomy for Natural History magazine, the Farmers' Almanac and other publications, and he is also an on-camera meteorologist for Verizon FiOS1 News in New York's Lower Hudson Valley. Follow us on Twitter @Spacedotcom and on Facebook. Original article on Space.com.