By Eric Holthaus

Just before sunset Sunday evening, millions of people across the western U.S. and around the world will be treated to an astronomical spectacle: an annular (or, “Ring of Fire”) solar eclipse. Although not quite a total eclipse — one in which the moon’s shadow completely covers the sun, prompting a midday darkness so deep that it brings out the stars — this weekend’s celestial treat will temporarily block up to 86% of the sun over some of the most photographic scenery the country has to offer.

Associated Press
An annular solar eclipse is seen in the sky over Male, Maldives, Friday, Jan. 15, 2010.

Below, I’ll share a few safety tips and my plan for viewing this eclipse. At my location in Tucson, Arizona, this will be the most complete eclipse until 2071. If you’re like me and don’t want to wait that long, read on for what you’ll need to know.

Send the WSJ your eclipse photos! Take photos of your eclipse-viewing equipment and gear, your viewing party and any shots of the main event you are lucky enough to capture. Post them to TwitPic or Instagram with the hashtag #eclipsed. If you would like to email your photos, send them toyourphotos@wsj.comInclude your name and location, and what you’re doing to view the eclipse. We’ll be rounding up the best photos and displaying them on WSJ apps and next week.

May 20, 2012 Annular Solar Eclipse Viewing Guide

Although solar eclipses happen regularly around the world, this weekend’s eclipse will be the first in the continental U.S. in more than 18 years. I remember watching that eclipse from my middle school in Kansas, and the eerie feeling as the sky darkened and the warm spring air cooled noticeably. Under every tree, the eclipse was replicated thousands of times as holes in the leaves formed tiny pinhole cameras.

A common misconception among would-be eclipse viewers is that enjoying the event requires special, expensive equipment. Not so. Although Albert Einstein famously used a solar eclipse in 1919 to prove his theory of relativity, you won’t have to be a physicist to enjoy Sunday’s show. You may impress your friends even more by trying a creative, lower-cost viewing trick (more on that below).

The moon passes between the sun and the earth during an annular solar eclipse over the skies of the Rift Valley town of Nakuru, west of Kenya’s capital Nairobi, January 15, 2010.

What’s happening?

The eclipse dance is performed due to the unique geometry of the Sun and Moon as viewed from Earth (the moon is 400 times closer, but the sun is 400 times bigger). Since the moon has a slightly oval-shaped orbit around the Earth, some solar eclipses are more “total” than others. At the moment, the moon is a bit further from the Earth than normal, so it won’t quite be big enough to completely block out the sun. (Bummer, I know.) As a result, this eclipse is an “annular” one, known for creating a “ring of fire” in the sky. Interestingly, this eclipse will also be a time-traveler: it will start in Japan on a Monday, cross the International Date Line, and finish in Texas on a Sunday.

Where to watch?

In the U.S., this year’s eclipse will traverse a 200 mile wide arc from Oregon to Albuquerque. (Find viewing times for your location from NASA) At the time of maximum coverage, the sun will briefly appear as a fiery donut hovering above the horizon. To most viewers west of the Appalachians outside this zone, the sun will gradually disappear to eventually become a thin sliver throughout the late afternoon hours. Unfortunately, the eclipse will end before it arrives on the East Coast. If you do find yourself out East, tune in to Panasonic’s live video stream from Mt. Fuji. It’s directly in the path, and you won’t burn your retina by watching online.

With the eclipse happening with the sun near the horizon and taking place in especially scenic territory, there’s a great opportunity to capture amazing photos. The National Parks Service has scheduled public viewing events throughout the West. I’ll be setting up shop myself in Saguaro National Park, with a good unobstructed view to the west.

What to bring?: A Recommended Checklist

Special eclipse-viewing glasses: Most astronomy shops and National Park visitors centers will have cardboard glasses with protection from both visible and UV light. Regular sunglasses won’t cut it. If you do not purchase a set of these special glasses, do not look directly at the sun for any length of time. It’s not that the sun emits especially damaging “eclipse radiation”, it’s just that the sun is especially interesting during these few hours and people may be tempted to look more often or longer than a fraction of a second at a time.There are plenty of other ways to watch the eclipse without damaging your eyes. The highest grade of welding goggles will also protect your eyes, if you want to fully embrace your inner mad scientist persona.

Digital camera with solar filter: Pretty much any camera will do the trick (without filter), though you do not want to look through the viewfinder. Take special care at higher zoom settings not to damage your camera as well — we all remember what happened to the ants in grade school when we turned our magnifying glasses into death rays. Nikon commissioned NASA’s eclipse guru Fred Espenak to write a guide to eclipse photography, which is worth a look, especially for advanced photographers trying to capture that once-in-a-lifetime shot.

Smartphone: As the first solar eclipse on the mainland U.S. in the digital media era, Twitter and Facebook feeds will be no doubt buzzing with photos for days. The appropriately named “Annular Solar Eclipse 2012″ app for iPhone gives local times and eclipse charts, along with a countdown to maximum coverage. The “Go Stargaze” app, published by the Astronomical Society of the Pacific, allows users to find local eclipse watch parties to join in.

A friend: Who better to ooh and aah with?

Want to Get Really Geeky?

Make your own pinhole camera: This is quite possibly the most interesting (and safest) way to watch the eclipse. Poke a small hole into an index card, then use that pinhole to focus the sun’s image onto another card, your hand, or anything for that matter. You’ll be able to watch the progression of the eclipse without risking your eyesight, and wow others in your viewing party with some science in the process. Emily Lakdawalla from the Planetary Society outlines a step-by-step how-to. Even more creatively, the Exploratorium in San Francisco has a diagram on how to make a pinhole camera with a Pringles can.

Project the eclipse for all to see: If you have a pair of binoculars, or a telescope, you can project a larger image of the eclipse onto another surface. But be careful if you don’t have a filter, you may inadvertently light something on fire. Needless to say, do NOT look through the eyepiece if you try this one.

Watch the leaves: As with my middle school experience in Kansas, sometimes nature provides the best viewing mechanism.Tiny holes in leaves will act as pinhole cameras, turning shade trees into eclipse factories. The result is magical.

Draw, paint, or write: Find another non-photographic way of recording your eclipse-viewing experience and share it with us on Twitter @WSJweather #eclipsed, or take photos and send them in via TwitPic or Instagram with the hashtag #eclipsed. We’ll include the best submissions in our eclipse wrap-up coverage.

If all else fails and it’s cloudy where you are (or you sleep through it), you could check out what a solar eclipse looks like from the space station, or just wait until the next one comes around. Comparatively, it’ll be a short wait: on August 21, 2017, a total solar eclipse will bisect a broad swath of the United States from Oregon to South Carolina — the first totality in the lower 48 since 1979.

Meteorologist Eric Holthaus contributes daily weather reports and analysis onMetropolis. For the latest on conditions in New York and elsewhere, follow his updates (@WSJweather) on Twitter.

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