People have big plans for getting the perfect view of the total solar eclipse

At 67, Frank Cantelmo doesn’t know how many more times he’ll be able to ride halfway across the country on his touring motorcycle, chasing the next big adventure.

So in January, when the retired sea captain read in the Old Farmer’s Almanac that a total eclipse of the sun would be visible within a distinct path that cuts diagonally across the country, the first time that has happened here since 1918, he immediately started mapping out his trip.

Later this month, Cantelmo will pack up his Honda Goldwing F6V and travel with a group of friends by motorcycle from Marshfield to a campsite in Tennessee, a spot within the so-called path of totality — the swath of communities that will be cast in shadow — where the view is expected to be perfect.

“I’ve never seen one before,” said the Marshfield resident. “And from what I’ve read on experiencing a total eclipse of the sun, it’s like nothing else you have ever experienced before. They say you see things with your eyes that you can’t even photograph.”

Cantelmo is among the thousands of people who for months have been planning for the celestial event. Many have vowed to uproot their lives leading up to the Aug. 21 eclipse, so they can bear witness to the otherworldly spectacle — and maybe pick up a commemorative T-shirt along the way.

According to the National Aeronautics and Space Administration, the total solar eclipse will be visible from within a 70-mile-wide corridor that cuts from Oregon to South Carolina. NASA’s website says the path of the moon’s “umbral shadow” will start in the northern Pacific, crossing from west to east. States, like Massachusetts, that aren’t within that path will still experience a partial eclipse.

A solar eclipse occurs when the moon passes between the sun and the Earth, temporarily blacking out the blazing sphere. It’s a rare chance for people to behold the sun’s corona, the outermost part of its atmosphere.

At the eclipse’s peak, which will last around two minutes, day will suddenly seem like night. Birds will likely stop chirping. It will get slightly cooler. Basically, experts say, it’s a bit eerie.

“It’s weird,” said Kathy Reeves, an astrophysicist at the Harvard-Smithsonian Center for Astrophysics, a combination of the Smithsonian Astrophysical Observatory and the Harvard College Observatory, in Cambridge.

Reeves, whose research focuses on the sun, is going to Oregon for the eclipse. Although she has seen one before — in 2012 she traveled to Australia for it — the occasion is still special. She said 1979 marked the last time a total eclipse could be seen from US soil. Even more rare? It’s been 99 years since such an eclipse was visible all across the continent.

Reeves plans to camp out with the Oregon Star Party, a nonprofit that meets annually in the Ochoco National Forest to observe the stars at night with telescopes.

“This year, of course, we’ll look at the eclipse during the day,” Reeves said. “It’s going to be a lot of fun.”

Oregonians aren’t the only ones who have been planning ahead. Cities and towns that fall within the path have been organizing and promoting events centered on the eclipse.

Officials in Tennessee, for example, are expecting a crush of tourists the weekend before Monday’s eclipse. Nashville is the largest city that falls within the path of totality, making it a draw for Northeastern travelers.

Butch Spyridon, chief executive of the Nashville Convention & Visitors Corp., said there’s been a noticeable uptick in hotel room reservations in Music City. If you’re hoping to find a place to stay the night before the eclipse — good luck.

“The city is completely sold out on Sunday night,” he said. “Sunday is typically the slowest night of the week, and that’s completely full.”

Spyridon said the city will be all-hands-on-deck to prepare for the moment the moon blots out the sun. They’ve made posters and will distribute special viewing glasses, to keep people from damaging their eyes; the science museum will become ground-zero for educational opportunities; and the Triple-A baseball club will let people watch the eclipse from inside its stadium.

They even have commemorative T-shirts.

“So if people wanted to say, ‘I was in Nashville on this date,’ we designed something they could take home with them,” Spyridon said. “We are extremely fortunate and blessed and appreciate our geographic position, and that we get to celebrate it with the world.”

Belmont resident Franko Kosic-Matulic is headed south with a caravan of friends. But the group will avoid the crowded city.

Instead, the convoy will drive to Crawford, Tenn., where they’ll camp in the woods at a site directly in the path.

“I want to go down to the fertile, beautiful South and kind of imagine what it’s like to have the sun disappear,” Kosic-Matulic said. “I think it’s going to be a really good end-of-the-summer kind-of marker, kind of like the last hurrah.”

While some will spend their time in the dark with friends, others are using the rare event as an excuse to reunite family.

Matt Berger, of Ashland, is traveling to Columbia, S.C. He said family will fly in from Florida, New Jersey, and California to join him at his father’s house.

“We’ll hang by the pool, have a couple beers, and see an eclipse,” he said. “Hoping to not burn out our retinas.”

Berger, 32, isn’t sure what to expect during the pivotal moment when the moon passes in front of the sun, though he’s heard varying accounts.

On the one hand, he said, people have told him that he’ll feel a deep connection to the physical world and his place in the universe. And on the other, they’ve described a feeling of being in another dimension, under an alien sky.

He’s eager to find out for himself.

“I hope it’s the first thing,” he said. “The surreal aspects would be pretty cool, too.”