The path of Monday’s solar eclipse across the continental United States. The moon shadow will begin to shade the sun and its shadow will be seen at about 9 a.m. PDT and cross the U.S. until it passes over the Atlantic Ocean about 4 p.m. EDT. Map courtesy National Aeronautics and Space Administration

On Monday, Aug. 21, a total solar eclipse will pass across the continental United States and though total eclipses are not rare, one passing across the U.S. is not common. The last opportunity was in 1979.

A total eclipse is when the moon passes between the Sun and the Earth. Essentially, the Moon’s shadow falls on the Earth.

The path of the “total” eclipse will cross 14 states starting in Oregon at about 9 a.m. PDT. It will go east over Idaho, Wyoming, Montana, Nebraska, Iowa, Kansas, Missouri, Illinois, Kentucky, Tennessee, Georgia, North Carolina and South Carolina and onto the Atlantic Ocean at about 3 p.m. EDT. The last viewing site will be near Charleston, South Carolina.

The eclipse will take about three hours to cross the U.S. but the longest period to observe the total eclipse will only be about 2 minutes and 40 seconds, according to the National Aeronautics and Space Administration.

Many hotels and inns along the totality path have been sold out for a year or more. The total eclipse’s path width is estimated to be 60 to 70 miles wide. Beyond that, distance viewers will observe a partial eclipse.

Idyllwild is not on the “totality” path of the “Great American Eclipse.” However, all of the U.S., including Idyllwild, can observe a partial eclipse. Locally, about 65 percent of the shadow will be seen.

But seeing is the danger. Do not look directly at the sun. Too much sunlight will damage the retina.

The Idyllwild Library will have “solar” sunglasses, which will protect the eyes. NASA stressed that even dark sunglasses are not absolutely safe eye protection. Special solar sunglasses are recommended, especially for viewing a partial eclipse where the sun’s corona is not fully obscured.

NASA will offer live online video streams of the eclipse at www.nasa.gov/eclipselive.

The next total eclipse to cross the U.S. will be in 2024, when the path will begin in Texas and move north over New England.

Idyllwild Library will have special events, Librarian Shannon Ng said. The first precedes the solar event and prepares viewers.

At 2 p.m. Saturday, Aug. 19, John Garrett will discuss eclipses, their history and the science behind the event.

On Monday, the eclipse day, the library will have a solar eclipse viewing party, which includes the live streams from the NASA videos, special children’s events, and in the afternoon, two movies that depend upon eclipses for their plots — “A Connecticut Yankee in King Arthur’s Court” and “Ladyhawke.”

Also, the Palm Springs Aerial Tramway will open early Monday for eclipse viewing. Ticket sales begin at 7:30 a.m. with the first tram car leaving the valley about 8 a.m. Mt. San Jacinto State Park Interpreter Allison Barnes will lead the program from the viewing deck of the Tramway’s Mountain Station. The Park will provide NASA-approved solar-viewing glasses (for the first 50 people) and a telescope with solar filter.

Idyllwild School students, wearing special solar glasses, will gather on the athletic fields to view the event, according to Principal Matt Kraemer.