It's being called the “Great American Eclipse” and has the potential to turn residents from casual sky observers into umbraphiles (“eclipse chasers”).

It’s being called the “Great American Eclipse” and has the potential to turn residents from casual sky observers into umbraphiles (“eclipse chasers”).

On Monday, Aug. 21, a total solar eclipse will make its way across the continental United States.

It will mark the first time in nearly four decades since the last total solar eclipse was viewable from the contiguous United States.

It’s also the first total solar eclipse with a trajectory exclusive to the United States since the birth of the nation in 1776.

“We’ve had a lot of questions and a lot of interest and inquires about the eclipse,” said Alan Sheidler, president of the Popular Astronomy Club of the Quad Cities.

During a total solar eclipse, the moon passes between the earth and the sun, blocking the light.

The eclipse will make landfall in the U.S. near Salem, Ore., and will continue diagonally across the country to Columbia, S.C. The eclipse’s path of totality touches 14 states, including the southern part of Illinois.

Geneseo falls about 200 miles north of the “path of totality” so the moon won’t entirely block the sun.

“It won’t get dark here. There will only be about a 90 percent coverage of the sun,” said Sheidler. “It’s still going to be strange. If it’s a bright, sunny day, you’ll see the brightness of the sun diminished. It will feel like a cloudy, overcast day. Only the sun won’t be covered by clouds.”

Those in places like Carbondale will be in the 70-mile wide “path of totality” and will experience darkness. “In the path of totality, they’ll be able to see the stars in the middle of the day.”

In Geneseo, the eclipse will start at 11:49 a.m. on Monday, Aug. 29. The eclipse’s will hit its “max” point at 1:15 p.m. and will end by 2:39 p.m.

“There will be some rather strange visual effects if people are observant,” said Sheidler. The moon’s blockage of the sun should result in “crescent shaped” shadows — especially if viewed through a pinhole.

“If you have a small aperture where the sunlight can pass through, you won’t see the normal round sun image. You’ll see crescents, but those will be interesting.”

The approaching eclipse also has created a demand for the special glasses needed to view the eclipse.

It’s dangerous to look at the sun during an eclipse. Looking at the sun while wearing regular sunglasses is unsafe and using binoculars or telescopes without the proper equipment, including solar filters, can severely damage your eyes.

The Geneseo Public Library received a grant from NASA to provide 1,000 solar eclipse glasses.

As part of the grant stipulation, half of the glasses had to be shared with other libraries. The remaining half were distributed to Geneseo patrons.

“At first we let people take up to four glasses, then we had to limit it to two,” said Geneseo Library Director Claire Crawford. “We had no idea the glasses would go so fast.”

Crawford said 100 eclipse glasses were reserved for patrons attending a special solar eclipse program at the library at 2 p.m. Saturday, Aug. 19. The program will be led by earth science teacher Becky Potenberg.

“After that, we’ll give the remaining glasses to those attending the program, but you have to attend the program to get the glasses,” she said. “Once they’re gone, they’re gone.”

Crawford said she and fellow library staff members had no idea how popular the Great American Eclipse would become.

“Everyone from children to senior citizens is interested,” she said.

During the solar eclipse itself, members of the public are invited to visit the library to watch the You Tube coverage of the eclipse.

“I think most people will probably step outside at their homes to watch it,” she said.

The mission of the Popular Astronomy Club of the Quad Cities is to introduce the public to astronomy. Events like the Great American Eclipse help capture the public’s imagination, said Sheidler.

“Part of our mission is to educate the public and answer questions and explain what’s going on. We try to utilize opportunities like this that don’t happen very often to get people of all ages — particularly children — involved and interested in science,” he said.

In the past decade, rare transits (when a planet passes in front of the sun) of Mercury and Venus attracted attention, but nothing like the upcoming total solar eclipse.

“Anytime there’s something going on astronomically that generates enthusiasm and interest from the general public, it’s an opportunity for us to talk about it and share our own interest and hobby,” said Sheidler.

“Astronomy is the best because it has something from all the other branches of science. If you’re interested in chemistry, physics, orbital mechanics, engineering, weather, nuclear fusion, computers, optics, whatever, it can be studied under the umbrella of astronomy. It can even appeal to those interested in photography or people who just want to appreciate the beauty of space,” he said.

Club members meet monthly — weather dependent — in the Niabi Zoo parking lot to gaze at the sky. Monthly observations usually take place at dark on the third Saturday of each month.

However, in August, the club will meet on a Friday night instead. On Aug. 19, members of the public are invited to join club members at the Niabi Zoo parking lot.

“We’ll set up our telescopes and let people look up and we’ll explain what they’re seeing,” said Sheidler. During the Aug. 19 event, members also will discuss the approaching eclipse.

Prior to the approaching Aug. 21 eclipse, the last total solar eclipse in the United States was in 1979, but Americans won’t have to wait that long for the next one. A solar eclipse is next scheduled to travel from Mexico diagonally up through New England in 2024.