A local geographer draws the lines between sunlight and totality of eclipse

Apr. 5—Michael Zeiler knows it might sound wrong from every angle, but he wants you to have the best possible total solar eclipse experience when it crosses North America on Monday, April 8.

So if you're traveling to San Antonio next week, he suggests staying away from the viewing party at the city's most famous landmark.

"The slogan is 'Forget the Alamo,'" Zeiler says. "You would think that would be a cool place to see it. It's historic. It's scenic. But it's outside the path [of totality]."

But it's close, he says, adding, "They only have to travel a few miles, probably four or five miles, to see the main attraction."

Zeiler, a former geographic information systems cartographer who lives in Santa Fe, knows the intricacies of attending a total eclipse better than most. He's even perfected the science associated with tracking the eclipse, and he shares the results on his website, greatamericaneclipse.com.

Zeiler was the first person to take the moon's topography into the calculation when forming an eclipse map, and now even NASA shares links to his maps on its eclipse page.

SUN SPOTS

We won't experience totality here in New Mexico, but that doesn't mean we can't appreciate the astronomical phenomenon in some form here.

Michael Zeiler, a Santa Fe resident and the founder of eclipse website greatamericaneclipse.com, says people who aren't traveling for the event can make the best of it here by finding a beautiful spot in nature.

"Probably the coolest thing to see during a partial eclipse is the crescent shapes on the ground underneath trees," he says. "The gaps between the leaves are actually like pinhole projectors, and they cast the shape of the crescent sun onto the ground."

However, there's just one problem: This time of year, the local aspen trees aren't leafing and leaves on many other trees are still in the early stages of returning for spring.

However, eclipse watchers can approximate the same effect with a kitchen tool. "If you use a colander or a grater — something that's perforated — and project it on a white sheet," he says, "You'll see an amazing array of crescent shapes."

In addition, two places in New Mexico are celebrating the eclipse.

The New Mexico Museum of Natural History & Science's Solar Eclipse Day is 10 a.m. to 2 p.m. Monday, April 8. Visitors can wear their eclipse glasses or watch the eclipse through a telescope. The museum will also offer a planetarium program about the eclipse that's included with the price of admission.

1801 Mountain Road NW, Albuquerque; 505-841-2800; nmnaturalhistory.org

El Malpais National Monument, 138 miles southwest of Santa Fe, is open for viewing of the partial eclipse from the vantage point of the visitors center. The event begins at 11:15 a.m. on Monday, April 8.

1900 E. Santa Fe Avenue, Grants; 505-876-2783; nps.gov/elma/index.htm

"If you look at the moon even through binoculars, you'll see that there's mountains on the edge," he says. "I pioneered the computation of taking all the little parts of the moon's terrain into account to make extremely precise eclipse maps. In the past, the maps were accurate to maybe four or five seconds. But now they're accurate to less than a second."

How did he do that? His computer ran for weeks doing calculations of the moon, and he then turned the math into maps. Zeiler's fascination with solar eclipses began in 1991, and he's seen 12 total eclipses on six continents. He was planning another trip to see a total eclipse in Antarctica during the pandemic, but the trip was canceled due to travel restrictions.

Zeiler started his website in 2009, which has become like a second job in retirement, he says. A lot of people are fascinated by eclipses, and Zeiler says if you're willing to travel the world, you'll find plenty of opportunities to see an eclipse.

"The next one in the U.S. is 2033 up in Alaska," he says. "Before 2017, we had a 38-year drought of total solar eclipses in the contiguous U.S. And now we've had two in seven years. It's kind of a random distribution, and it happens that way sometimes. What's coming up is the country of Spain gets two total solar eclipses in 2026 and 2027."

That phenomenon is extraordinarily rare. Zeiler says the average distribution of total solar eclipses to any given point on Earth is once every 375 years. He notes that New Mexico has seen a slightly less rare occurrence, the annular eclipse, three times over the last 20 years, including last October.

"Why annulars sometimes happen versus totals is because the moon is in a slightly elliptical orbit around the Earth, and the Earth is in a slightly elliptical orbit around the sun," he says. "It depends on where we are in those orbits, whether we're a little bit closer or a little bit farther, and that's the fundamental reason we sometimes have one or the other."

A partial eclipse — which Santa Fe will experience April 8 — occurs when the center part of the shadow just misses the earth above the North Pole or below the South Pole. Zeiler says Santa Fe will see a 73 percent eclipse on April 8, and the peak of the phenomenon will occur at 12:30 p.m.

You'll still see daylight. It will be dim, eerie daylight. But while a partial solar eclipse is cool, Zeiler says it really bears no resemblance to experiencing the full one.

"I get this every day. People get the idea that if they're just outside the path — if they're at 95 or 99 percent partial eclipse — that they're going to see most of the eclipse," he says. "But the reality is 99 percent partial eclipse equals zero percent total eclipse. You really need to get inside the path of totality. Our mission is basically to educate people that this is really a bucket list item, that it'll be a peak life experience, and it'll be worth the effort."

If you're in the path of totality, Zeiler says, you will be able to take off your glasses and look directly at the sun. But if you're watching a partial eclipse — like everyone in New Mexico will be on April 8 — there will be no point during which it's safe to remove protective glasses. The totality of this eclipse will last four minutes, says Zeiler; the longest one he's seen stretched over six minutes and 50 seconds in Baja California, Mexico.

"We wear the glasses for the partial stages of the eclipse," he says. "But once it's total — and there will be no doubt once totality begins because it will be a sudden sweep of darkness enveloping you — then you take the glasses off.

"It's safe to look directly at the corona for those four minutes, and it's safe to use regular binoculars for those four minutes. Outside of those four minutes, we only look with the proper solar filters."

Zeiler says he tries to see every solar eclipse he can make it to, and after this week's event, he says he's looking forward to one that will occur in 2045 over Montana and North Dakota. Zeiler will be 89 by then, and he says the totality of that eclipse will last for more than six minutes.

After experiencing 12 total eclipses, what keeps him wanting to see more of them?

Zeiler says that each eclipse is unique, and he relishes the opportunity to see what each one brings to the experience.

"The sun's activity is always changing. The corona is shaped by the intense magnetic fields of the sun," he says. "We've seen eclipses that were just above the horizon versus straight overhead. It's the most beautiful sight you can see with your eyes. For those few minutes, it's like you're in a science fiction movie. It's like being on another planet where it looks completely different from what you're used to, and we go to great lengths [to see them]."

Last year, Zeiler flew across the world to Australia for a total solar eclipse that only lasted 59 seconds. And he says it was totally worth it.

"That was particularly dramatic," he says. "There were lots of fireworks. ... You can see a lot of activity in the corona, and it's different every time."

Visit greatamericaneclipse.com or science.nasa.gov/eclipses for more information.