May 18, 2012 at 2:50 AM ET
If the weather cooperates, millions of people can witness Sunday's rare "Ring of Fire" solar eclipse — but what if you're one of the billions who can't? You can still watch the event online.
That's what Alan MacRobert, a senior editor at Sky & Telescope magazine, is planning to do. He's based in the Boston area, where not a bit of the annular solar eclipse will be visible. So MacRobert will be cruising the Internet, looking for a webcast with a stable video stream.
He should have plenty of webcasts to choose from. "There are more popping up as we get closer to the event," he told me.
Sunday's spectacle isn't your garden-variety solar eclipse: Because the moon is farther away from Earth than usual, the angular size of the lunar disk isn't quite wide enough to cover up the sun completely. Thus, at the peak of the eclipse, a thin ring of the sun's bright photosphere will remain exposed around the moon's dark circle.
That's what's known as an annular eclipse, which gets its name from the Latin word for "little ring": annulus. The little ring can be seen from a 200-mile-wide strip of territory, extending from southern China, through Japan, across the North Pacific and over to the U.S. West Coast. From the Oregon-California border, the strip goes across parts of Nevada, Utah, Colorado, Arizona, New Mexico and Texas.
The "Ring of Fire" effect lasts just a few minutes. For about an hour before and after the big event, a partial solar eclipse will darken the sun and then retreat. The partial phase can also be seen to varying degrees from a much wider swath of eastern Asia, the Pacific and North America.
If you're in the eclipse zone, do not gaze at the sun without taking proper precautions. Such precautions can range from eclipse-viewing glasses, to specially designed solar filters, to pinhole projectors. Check out this NASA Web page or this video for the details. Here's a detailed video about eye safety from Eyes on the Sky. (Thanks, @AstronomyDave!)
If you're not in the eclipse zone, you're not alone: The U.S. East Coast, South America, Europe, Africa, Australia and Antarctica will be totally left out. And let's face it: Even if you are in the zone, the weather may not cooperate. That's especially the case for places like Hong Kong and Guangzhou, where millions might miss the annular eclipse due to cloudy skies. "This is monsoon season in south China, so they're going to need quite a bit of luck to have a chance of seeing this one," MacRobert said.
Watching the eclipse via a webcast isn't a sure thing, either. The skies might be clouded over at the camera location. There could be technical difficulties. And even if everything works, the webcast could freeze up if the video server becomes overwhelmed with traffic. That's why MacRobert is planning to play the field, and why you'd be best advised to do the same. Here are a few of the options for Sunday eclipse views over a computer screen or smartphone:
Slooh Space Camera: The Slooh website has organized a series of webcasts from Japan, California, Arizona and New Mexico, accompanied by commentary from Astronomy Magazine columnist Bob Berman and Lucie Green, a BBC commentator and solar researcher at University College London's Mullard Space Science Laboratory. The show gets started at 5:30 p.m. ET Sunday, when the eclipse will be just getting good in Japan. Prime time for the webcasts from the American West will kick in around 8 p.m. ET. For more, check out Slooh's news release.
Eclipse Live from Fujiyama: Panasonic is planning a solar-powered webcast from high atop Japan's Mount Fuji, which is inside the track of annularity. The team will charge up batteries from an array of electricity-generating solar cells at a base camp, then carry the batteries up to the camera site. Video coverage via Ustream is due to start up at 5 p.m. ET. This YouTube video previews the event. For updates, check out the project's Facebook page and Twitter stream.
Hong Kong Observatory: The webcast from Hong Kong is due to begin at 5:41 p.m. ET.
More from YokosoNews: This page from the Japanese news site lists lots of webcasts, generally beginning at 5 p.m. ET or later.
More from Ustream: Do a search on "eclipse" and you'll find all sorts of Ustream goodies, from 5 p.m. ET onward. One user is promising a video stream from the northern tip of Taiwan starting at 4:50 p.m. ET.
University of North Dakota: UND's SEMS (Sun Earth Moon Systems) team is organizing an eclipse webcast from Shasta College in Redding, Calif. The streaming is due to begin at 8 p.m. ET, and there's a chat window that lets you compare notes with other eclipse fans. The UND team has been doing eclipse webcasts since 2004, so they've built up a loyal following over the years.
Scotty's Sky: Skywatcher Scotty Degenhardt is promising an unconventional webcast of the annular eclipse via his iPhone from Area 51's "Black Mailbox," a popular gathering place for UFO fans in the Nevada desert. The show is set to start at 8:10 p.m. ET. Check out Degenhardt's website for the details.
Exploratorium in Second Life: Speaking of "unconventional" ... San Francisco's Exploratorium science center is planning to provide information about the eclipse in the Second Life virtual world. If you're a Second Life resident, set a course for Exploratorium Island.
If you're wowed by webcasts, stay tuned: There'll be another big event on June 5, when the planet Venus makes a must-see transit across the sun's disk; and again on Nov. 13, when a total solar eclipse takes place.
Are there any annular eclipse webcasts I'm missing? Pass 'em along in the comment section below.
Update for 12:10 p.m. ET May 18: To find out whether any part of the eclipse will be visible from your locale, consult this clickable map from NASA. The times are listed in UTC. Subtract four hours to convert to ET, five hours for CT, six hours for MT, seven hours for PT.
Correction for 4:50 a.m. ET May 20: I mistakenly placed Shasta College in Whittier, Calif., rather than Redding. That reference has been fixed ... sorry about that.
More about the eclipse:
Alan Boyle is msnbc.com's science editor. Connect with the Cosmic Log community by "liking" the log's Facebook page, following @b0yle on Twitter and adding the Cosmic Log page to your Google+ presence. You can also check out "The Case for Pluto," my book about the controversial dwarf planet and the search for new worlds.