Eclipse 2017: Darkness is Coming

Totality's eerie light bathes the ring of massive monoliths while robed figures chant and burn their sacrificial offerings. Around them, the gathered throngs raise their voices in joy and smile for the cameras of the CBS Evening News. It is 1979, and the scene is a bizarre roadside re-creation of Stonehenge overlooking the Columbia River in western Washington state. Neo-pagans and curious onlookers have amassed to witness the rare event unfolding overhead, and this being Washington (and the 1970s), it's clear that not all the smiles and good vibrations are due solely to the solar eclipse.

Back in the studio, Walter Cronkite tells us there will not be another total solar eclipse to touch the continental United States this century. Not until the far-off date of 2017 will totality once more be so visible to so many on this continent.

I've been waiting to see this eclipse ever since.

The Feb. 26, 1979, eclipse only touched a corner of the U.S. before swinging up into western Canada, and not even half of today's Americans were alive for it. A continent-spanning eclipse hasn't occurred in the U.S. since 1918, almost 100 years before what is being called the Great American Eclipse of 2017. When the current drought of 38 years without a total solar eclipse ends in 2017, it will mark the beginning of a new 38-year period in which Americans will get to see five (in 2017, 2024, 2044, 2045 and 2052).

Over time, these cycles of bounty and absence come and go, and every place on Earth is crossed eventually. For human beings, with our limited lives and limited means of travel, these vagaries of celestial alignment mean the majority of people on Earth have never seen a total solar eclipse.

The first total solar eclipse most Americans will have ever seen begins the morning of Monday, Aug. 21, 2017, two seconds before 10:16 a.m. PDT. At that moment, the dark shadow of the moon touches the Paciific Coast at the Yaquina Head lighthouse outside the coastal town of Newport, Ore. There is no doubt about this. Astronomers have a bad reputation for predicting amazing sights for the public. Too many "Comets of the Century" turn into faint fuzzy duds that disappoint in the darkness. Too many meteor “storms” wind up being no more than a drizzle once you've woken the family at 2 a.m. But this eclipse is happening, in the middle of the day, exactly on time, and in exactly the places that are predicted. It’s as certain as the sunrise.

The only question is a matter of clouds, and even those can be forecast with some certainty. The region with the best chance of clear skies all along the path of totality on that date is eastern Oregon, which the moon’s shadow reaches at 10:19 a.m. and 36 seconds PDT as it crosses the Cascade Range and lies eastward at a speed of 2,265 mph.

At 2:47 EDT, one hour and 33 minutes after coming ashore on the Paciifc Coast, the moon’s shadow crosses out into the Atlantic just north of Charleston, S.C. In that time it will have touched 13 states, five state capitals, and 9.7 million residents, not counting the millions who will travel into the path to see it. Totality — when the sun is completely blocked by the moon — will take only 93 minutes to cross from sea to shining sea.

But not all views are equal.

Although all of North America will witness at least a partial eclipse, the real show is within the zone of total darkness. You must get into the umbra, the darkest part of the moon’s shadow where the disk of the sun is completely covered. That is where the eclipse is total.

Those in totality’s path see Baily’s beads, when sunlight shines through lunar mountains, sometimes making the eclipsed sun look like a diamond ring. Totality also makes it possible to see the sun’s corona, or outer atmosphere, and any prominences extending from our star’s edge. Day becomes night and the brighter stars and planets, such as Venus and Mars, become visible near noon. You will understand the true meaning of awe. But the difference between being inside and outside the path of totality is the literal difference between day and night.

Those barely outside the path will not experience such darkness, and no stars or planets will become visible. Here, the Great American Eclipse will be only partial, and special eclipse glasses will be needed for the entire event.

I saw the 1979 eclipse, my first, in complete safety at home: in a darkened room, with all the windows covered, watching it on TV. I missed experiencing the greatest awe-inspiring wonder that nature has to offer because our local school officials — who felt eclipse watching was too dangerous for children and did not want to be held liable in the event of an injury — had issued overly cautious warnings. Regardless of whether those school administrators were right to be wary, not a year has gone by since that I haven’t felt cheated out of a life-changing experience.

That said, observing a solar eclipse can be dangerous if proper precautions are not taken. First, you may be wondering what the potential harm is. The un-eclipsed sun is visible every day, yet we don’t warn children to stay indoors on sunny days. The sun doesn’t emit any special rays during an eclipse, but how we behave toward the eclipsed sun does change. On a typical day, very few people willingly stare at the sun for a prolonged period of time.

Health officials’ concern during an eclipse is that people will stare at the sun, particularly close to totality when the sun may look like a crescent. People want to see this phenomenon, and so they will look longer than they should, placing its image on a single part of the retina. Since there are no pain receptors in the retina, the damage as it burns produces no discomfort but can be permanent.

The solution is simple: Never look directly at the partially eclipsed sun without proper eye protection. Either look through specially designed filtered glasses, or project an image of the sun on a screen, using a pinhole projector made from items found around the house or naturally outdoors. These two methods of seeing the partial phase of a solar eclipse are cheap, safe, and in the case of finding naturally occurring pinhole-projections, an enormous amount of fun.

If you miss the total solar eclipse of 2017 — or, having seen it, you catch the bug and absolutely must see another — don’t worry, there are many more coming.

The next total solar eclipse to touch the continental U.S. is April 8, 2024. On that day in midafternoon, the path of totality starts in Mexico, travels northward into Texas, and then crosses the central U.S. before passing through eastern Canada.

The residents of southern Illinois are the lucky ones: They will get to see two total solar eclipses in seven years without having to travel anywhere.

Perhaps the most spectacular views in 2024 will come for those on the U.S. side of Niagara Falls. From the railing beside the water, the totally eclipsed sun will hang directly above the crashing falls for 3 minutes and 30 seconds in what is sure to be a wild sensoryoverload spectacle of sight and sound — assuming it is clear at that time of year, of course.

Lest we forget total lunar eclipses, when our planet blocks sunlight from shining on its satellite, there is a special beauty to going out under a night sky brightly lit by a full moon. What begins with only a few stars visible against the glare of the moon slowly turns into a thousand points of light as the eclipsed moon darkens. By the time totality occurs, the sky is ablaze with stars; if totality occurs near the peak of a meteor shower, the dark-red moon can be surrounded by shooting stars for the duration of totality. I saw this in August 2007 from Grand Teton National Park immediately after the Perseid meteor shower with the Milky Way arching overhead; it was one of the most magical moments I’ve ever experienced. For such a night, consider the total lunar eclipse of July 27, 2018. It will occur two weeks before the peak of the Perseid shower, but a few meteors may be visible as the blood-red moon hangs beside the brightest portion of the Milky Way for witnesses in Europe and Africa through Asia.

Beyond 2030, we run into the conundrum that all eclipse-chasers ultimately face: How many more will life allow us to see?

The most widely available device for viewing the partial phase of a solar eclipse is simple, commercially available plastic or cardboard safety glasses. These glasses are inexpensive, typically $1 or $2, and are available from a number of websites. Local stores usually sell them in places where total eclipses occur. You should be unable to see anything other than the sun through the lenses of these glasses. The special solar filter in these glasses can be delicate. Any holes or scratches they develop make them instantly worthless and potentially dangerous. Keep them protected. If you have any doubts, hold them up to a lightbulb: If you see any light at all coming through the lenses, throw them away and use another pair.

The cheapest, simplest and absolutely safest method of watching a partial solar eclipse is to find a piece of cardboard and poke a small hole in it. Hold this outside and the sunlight passing through the hole produces an image of the sun wherever the shadow of the cardboard falls. Place a sheet of paper on the ground or on a wall and everyone can see the eclipse progress together. Do not look through the pinhole at the sun. One of the most enjoyable parts of watching a partial solar eclipse (or spending time outside in the sun waiting for totality to begin) is looking around for natural pinhole projectors. You can use leafy trees, woven hats, interlaced fingers, or any other place that tiny holes occur through which the eclipsed sun shines, casting myriad crescents into their shadows.

Stay away from people offering to let you look through makeshift items like dark beer bottles, silver candy wrappers, CDs or DVDs, smoked glass or dark sunglasses. These might make the sun look dim, possibly even dim enough to look at without discomfort, but they may do nothing to block infrared or ultraviolet radiation that will cause permanent damage to the retina and possibly lead to blindness.

Whether using filters or projection, once totality begins with the first diamond ring, you may put the filters and glasses aside and feel free to look at the sun with the naked eye in complete safety, until the second diamond ring marks totality’s end.

My simplest recommendation for photographing a total solar eclipse is this: Don't do it! Typically, you will have no more than two minutes of totality. That’s 120 seconds. Why spend those precious seconds looking down at your camera's instruction menu, trying to get your camera to focus, or working to get the exposure right? Professional photographers will surely be covering this celestial event, and it's safe to assume their pictures will be better than yours. If none of that dissuades you, here are a few tips for taking solar eclipse photos.

1. During the partial phase of the eclipse, do not point your camera at anything you wouldn’t look at with the naked eye. You may be able to safely look at the monitor on the back of your digital camera, but your camera lens is focusing the sun’s light on your sensitive camera optics. If you need a filter for your eyes, your camera needs one, too.

2. If you are using a filter for your camera during the partial phase, remember to take it off during totality or you won’t capture anything.

3. During totality, the sky darkens enough for the brighter stars to appear. In the days before totality, go outside immediately after sunset and wait until the first, brightest stars appear. This is a fair approximation of how dark it will be. Experiment with taking photos at this time. How do they come out? Do you need a tripod for your camera to successfully take sharp, nonblurry, non-grainy photos under these conditions? If so, this will be another piece of equipment you will need to handle during those precious seconds of totality.

4. It will be dark during totality, but do not use a flash. It will blind everyone around you at exactly the moment they want to see the sky the most. Turn all flashes off.

5. The full moon is about as bright as the corona. Try taking photos of the full moon to see how long you need for it to be properly exposed. Again, does this require a tripod?

6. The full moon is also the same size as the sun and will be the size of the “hole in the sky” during the eclipse. Practice using your camera to photograph the full moon. How big does it appear in your image? Is this worth taking a picture of? Many of the best eclipse photos that show details of the corona and prominences use telephoto lenses with focal lengths of at least 500 millimeters, but they cost thousands of dollars.

Adapted excerpt from "Sun Moon Earth: The History of Solar Eclipses from Omens of Doom to Einstein and Exoplanets" by Tyler Nordgren. Copyright © 2016. Available from Basic Books, an imprint of Perseus Books, LLC, a subsidiary of Hachette Book Group, Inc.