In ancient days, people believed a solar eclipse was a monster gobbling up the sun.

Now, the event is a spectacle of fascination rather than fear.

Today, clear skies in Arizona are expected to feature one of the most striking eclipses in the past few decades. The partial eclipse will begin just before 5:30 p.m. and last through sunset. At the height of the eclipse, around 6:35 p.m., the moon's silhouette will block 83 percent of the sun's surface area in the Phoenix area and 87 percent in Flagstaff.

The eclipse, which will be visible from eastern Asia to the western U.S., is generating a lot of interest. National parks in Western states are planning viewing parties.

"You'll have the cacti in the foreground, the mountains on the horizon and the setting solar eclipse. That is a spectacular view," said Adam Block, manager of public-observing programs at the Mount Lemmon SkyCenter northeast of Tucson.

The view of the eclipse in northern Arizona is expected to be especially impressive because the moon will pass entirely in front of the sun, creating a brilliant ring of light known as a "ring of fire." The view in the southern two-thirds of Arizona is expected to be a broken ring of light.

Solar eclipses that can be seen in the United States happen periodically and are of different types. The last total eclipse in the U.S. -- in which the moon blocks out the sun entirely -- occurred in 1991 and was seen in parts of Hawaii. The last one on the mainland was in 1979. The next total eclipse in the U.S. will be Aug.21, 2017.

Today's eclipse is called an annular because the sun becomes a ring encircling the moon. It's the first ring eclipse in the United States in 18 years.

The moon's silhouette initially will look like a dark dent on the sun, growing steadily larger until the sun becomes a bright, thin crescent. The sun will never be completely covered. Daylight will dim a bit, as if there is a thin layer of clouds.

Marc Neveu, a graduate student at Arizona State University's School of Earth and Space Exploration, is planning a trip north to get a better view of the eclipse.

Neveu, 24, is going to Page, a small city on the southern shore of Lake Powell in northern Arizona, where the landscape should produce amazing views.

He should have a lot of company. The eclipse has produced a run on hotel rooms in Page.

Evie Lane, office manager for the Page-Lake Powell Tourism Bureau, started getting calls months ago from people interested in coming to Page to view the eclipse. As of Friday, Page was almost sold out of hotel rooms, she said.

Members of the ASU Astro Devils, the university's astronomy club, plan to travel to Chinle on the Navajo Reservation, where the view is also expected to be spectacular.

Neveu has seen two other eclipses: a total eclipse in 1999 in France and an annular eclipse in 1994 in Detroit.

He said good viewing spots in the Valley include South Mountain,Camelback Mountain and Tempe Butte, also known as "A" Mountain.

There are several ways to watch the eclipse.

To avoid damaging your eyes, don't look directly at the sun unless you are wearing special solar-observing glasses. Sunglasses aren't strong enough. You can use a small telescope to project an image of the sun onto white paper.

You also can view the eclipse safely by making a pinhole camera using two thin pieces of white cardboard. Punch a hole with a pin in the center of one piece. Hold the paper up and aim the hole at the sun, allowing the light to fall through the hole onto the second piece of cardboard.

Thanks to the Internet, you can also watch the eclipse indoors. A network of telescopes, including ones in Arizona, will provide live feeds of the eclipse over the Web. Mount Lemmon SkyCenter will start its broadcast around 4:30 p.m. at skycenter.arizona.edu.

A telescope at the Grand Canyon will be part of a group of telescopes around the world that begins broadcasting live at 2:30 p.m. Arizona time, when the eclipse will be visible in Japan. The website can be accessed at www.slooh.com.

The Grand Canyon is among the national parks planning viewing parties. Rangers at the North Rim and South Rim will offer assistance with viewing; NASA scientists and amateur astronomers will be at the South Rim with telescopes. Most of the telescopes will be just west of the visitor's center.

Meteor Crater, 35 miles east of Flagstaff, will sell eclipse-safe glasses and have astronomy students from the University of Arizona help people watch the eclipse.

In Tucson, the Flandrau Science Center at UA will host a viewing party from

4 to 8 p.m., including the sale of solar-viewing glasses and presentation of its laser show of Pink Floyd's "Dark Side of the Moon." A party also is planned at the Mount Lemmon SkyCenter.

Robert Arnold of Flagstaff plans to watch the eclipse from an unusual location: amid pine trees 60 feet up in the air.

Arnold, 26, works at Flagstaff Extreme Adventure Course, a zip line and obstacle course in the trees. When work is over today, he plans to stick around to snap pictures of the eclipse. To get up there, he will climb a 30-foot cable ladder, travel more than 300 feet via zip line and climb another 30-foot ladder to a platform.

"I just think it's going to be awesome," he said. "This is one of the reasons I love living in Arizona, just being in a place well-known for our great views of the sky and stuff."

Today's eclipse is the first of two big sky-watching events this summer. On June 5, the shadow of Venus will pass in front of the sun, a rare event that last occurred in 2004 and won't happen again until 2117.