Getting Ready for the Eclipse

By Jay Pasachoff

A solar eclipse is a wonderful thing to see, and as an astronomer, I am trying to do my part to spread the word and teach kids how to observe it safely.

On August 21, the Moon will block the Sun as seen from North America and down through mid-South America. The path of totality, during which the everyday Sun is entirely blocked, will be about 60 miles wide and will go through parts of 14 states, from Oregon, Idaho, and Wyoming in the northwest, to, more than an hour later, parts of Illinois, Kentucky, and the Carolinas in the southeast.

Kids and adults in the path of totality will have an impressive experience, as the light outside darkens by a factor of about a million over the course of the hour before totality, including a final, dramatic factor of 10,000 in the last minute.  At that time, a “diamond ring” of sunlight will peer through a valley on the edge of the Moon for a few seconds, as the everyday solar disk is entirely covered.

Map by Fred Espenak,

For most people in the United States, the Moon will only partially cover the Sun. The remaining part of the Sun’s disk is so bright that you can’t look at it safely without using a special filter. These filters are so dark that only about one part in a million of sunlight comes through; you can use them on any day. The lenses darken the incoming sunlight by about the same factor as 20 or so sunglasses in a row, and also cut out incoming light (infrared, ultraviolet) to which our eyes aren’t visibly sensitive but could still be overloaded.

Those of us who think about education during eclipses are fanning out to try to tell as many people of all ages why it is interesting to see the eclipse and how to watch it safely.

Educating about an eclipse is important! Three years ago, a partial solar eclipse was visible in the western United States. I was in New Mexico for the eclipse itself—where no one, not even the local science museum staff, had prepared schools for the upcoming event. I had spoken in advance to my granddaughter Lily’s class of four-year-olds in Pasadena, California, however. During the eclipse, Lily’s teachers were able to take their classes outside and look through the filter material at the partly eclipsed Sun. Those kids, like the animals in the children’s book Someone Is Eating the Sun, witnessed what appeared to be a bite of ever-increasing size being taken out of our star!

This August’s solar eclipse will be partial throughout the United States, so I’ve been speaking at lots of schools, including Lily’s 1st grade at the Monte Vista School in La Crescenta, California, and her brother Jacob’s 4-year-old class in Pasadena. I spoke to two 2nd-grade classes at the Watkins Elementary School on Capitol Hill in Washington, D.C., where my grandson Sam is a student, and also to a pre-school class at the Peabody Elementary School, also on Capitol Hill, where Sam’s sister, Jessica, is a student.

I told them about how interesting it is to know that there will be an apparent bite out of the Sun, and that we astronomers can predict a lot about the universe. We hope that they will pay attention to their studies—and then they can one day understand the universe, too.

I always get lots of good questions—about the eclipse, about the stars, and usually also about black holes. And I have very nice thank-you notes with the kids’ drawings!

“Celestial Buddies” help illustrate an eclipse. Photograph by Deborah Pasachoff

I have a set of stuffed planets, “Celestial Buddies,” which are like stuffed animals but represent instead our solar system’s eight planets, the dwarf planet Pluto and its moon Charon, and a comet, as well as the Earth, the Sun, and the Moon. For each classroom demonstration, I took along the Sun, Moon, and Earth to show how eclipses happen. I emphasized that for the Celestial Buddies to be to scale, the Sun would be the size of the whole school building!

I also have a demonstration from the Astronomical Society of the Pacific that lays out a marble-size Earth and a much-smaller Moon at opposite ends of a foldable yardstick, to show how rare it is for the shadow of the Moon to actually hit the Earth, explaining why we don’t have an eclipse every month. In each school, my grandchildren have been my helpers, holding a Celestial Buddy in place along with friends as additional helpers.

What about the first eclipse for my newest grandson Xander, just short of 18-months-old on the day of the eclipse? We will certainly have him look—through solar-filtered glasses, of course! His mother, Deborah, saw her first total solar eclipse at the age of about six months, and appropriately cried at the sight, as though she knew something special was going on. So Xander isn’t even starting especially young, though Deborah’s sister, Eloise, was already two years old when watching her first solar eclipse.

It used to be that we would tell kids about using pinhole cameras—that is, making a hole about ¼-inch or so in a piece of cardboard and standing, with the Sun at your back, while looking at the projected image on a second piece of cardboard. Depending on how high the Sun was, you could even see images from the spaces between tree leaves overhead or on a wall.

Just looking away from the Sun in this way is obviously completely safe. But those pinhole images are pretty fuzzy, and the prices of solar filters have come down to a dollar or so (and less if bought in quantity). The filters are sometimes called “eclipse filters” or “eclipse glasses,” though they are usable any day. During an eclipse, however, they are meant to be used only during the partial phases; you would miss the amazing spectacle of totality, with the solar corona becoming abruptly visible, if you kept them on during it.

Photograph by Deborah Pasachoff

It’s fun to talk to the kids. I’ve been glad to have solar filters to distribute. In La Crescenta, the PTA is buying filters for the whole school at 25 cents each, and can send them home for parents to use. Some schools across the U.S. will be in session on August 21, while others will still be on summer vacation, so we hope that families can watch together.

I’ve also been speaking to my local schools in Williamstown, Massachusetts, where the Sun will be at most about 70% covered by the Moon on August 21, and at other occasions. We’d like all 300 million Americans to watch the eclipse!

Of course, I’ll be in totality along with my students, scientific colleagues, and others on August 21, and my family will be with me. I hope that families all across America and beyond enjoy the eclipse.

Jay Pasachoff is an astronomer who has received numerous grants from the National Geographic Society since 1973. He continues to lead cutting-edge research and observations of the heavens, in particular regarding eclipses.



2017 Eclipse

Maps and information about this eclipse

Past Eclipses

Books by Jay Pasachoff

American Astronomical Society on this Eclipse

NASA on this Eclipse

Maps of this Eclipse

Cloudiness Statistics and Weather Eiscussions on this Eclipse

Celestial Buddies

Solar Filter Information

“Solar Filters & Viewers,” from the American Astronomical Society

Thousand Oaks Optical

Rainbow Symphony

American Paper Optics


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