At 11:43 a.m., Monday, Aug 21, 2017, Casper will enter 146 seconds of total darkness as the moon blocks the sun for a total eclipse.

At 11:43 a.m. Sunday, dozens of city officials and well-wishers hoisted plastic glasses of champagne to toast the 365-day countdown leading to the Wyoming Eclipse Festival at a ceremony at Crossroads Park.

"Here is to totality one year from now," said Anna Wilcox, executive director of the Wyoming Eclipse Festival.

This is the first total eclipse in the United States since 1979. This one will track through the entire country including all of Wyoming. Casper is one of the largest cities to experience the totality of the eclipse, which will be 146 seconds.

This is rare, huge and a one-time event with no practice runs.

"One of the biggest goals is to make sure not only that we can handle the number of people, but to be great hosts to this number of people," Wilcox said.

She intends to meet with restaurants to show how they can be better hosts with people from other countries, Wilcox said.

Public safety also will be a major concern: "To make sure we have full coverage for all of the events that are happening, making sure that roads are cleared, what roads might need to be closed, what roads are evacuation routes."

And Casper itself needs to be educated about what will be happening. Wilcox has heard from others where eclipses have occurred.

The thousands of visitors knew what was going on in those cities, but the locals didn't, she said.

"A number of people showed up to work that day and said, 'where is everyone,' or even worse, 'oh my goodness, why is the sky getting dark,'" Wilcox said. "So I want to make sure that everyone in the community of Casper knows that it's happening, knows how to prepare for it, and knows how to get out there and enjoy it."

She declined to estimate the possible number of visitors. Previous estimates have ranged from 10,000  to 50,000. Estimates could be made about the bookings at hotel rooms and camping spaces, but they're probably faulty, she said. "Either way, I don't think its something to fear."

Many hotels have had rooms booked for a year or so. Some have not been able to start booking rooms until today, Wilcox said.

The Wyoming Eclipse Festival doesn't occur for just the two minutes, 26 seconds to totality, she said.

Some people will drive from Colorado and even Canada for one day, Wilcox said.

Others will want to stay a while.

Visitors will want to do other things, and the Eclipse Festival will be having other events for at least several days before the event itself. The Riverfest and Uprising concert festival this past weekend will be among the other opportunities for visitors, she said.

However, her organization doesn't need to do formal promotions simply because people will go where the eclipse is, which is here.

The Central Wyoming Astronomical Society will offer its own expertise and viewing opportunities, its president Alan Corey said.

Corey set up two telescopes capable of viewing the sun.

One was a conventional reflector scope with a Mylar filter that can see the outer layer of the sun.

The other was a hydrogen alpha telescope that takes the white light, splits it into all wavelengths and filters out everything except red, he said. That one can see into the sun's chromosphere, which is the second layer of our solar system's star.

The Astronomical Society wants to set up about 50 areas in the city with telescopes for locals and visitors to view the sun up close during the eclipse, he said.