The western United States and eastern Asia will be treated this weekend to a rare solar spectacle when the moon slides across the sun, creating a "ring of fire."
But scientists caution would-be viewers to be very careful because the sun's damaging rays will remain powerful even during the annular solar eclipse. The advice: Either wear specially designed protective eyewear or attend a viewing event _ at a planetarium or amateur astronomy club, for example _ to avoid risk of serious eye injury.
The solar spectacle will first be seen in eastern Asia around dawn Monday, local time. Weather permitting, millions of early risers in southern China, northern Taiwan and southeast Japan will be able to catch the ring eclipse.
Then, the late day sun (on Sunday in the U.S.) will transform into a glowing ring in southwest Oregon, Northern California, central Nevada, southern Utah, northern Arizona and New Mexico and finally the Texas Panhandle.
For 3 1/2 hours, the eclipse follows an 8,500-mile path with the ring-of-fire phenomenon lasting as long as 5 minutes, depending on location.
Outside this narrow band, other parts of the U.S. and portions of Canada and Mexico will be treated to a partial eclipse. The Eastern Seaboard will be shut out, but people can find online sites that plan to broadcast the event live.
It's impossible to know how many people plan to make an event of the ring-of-fire spectacle, the likes of which hasn't been seen in the continental U.S. for nearly two decades.
One clue to demand might be found at the planetarium at the University of Nevada, Reno, which had to order another 10,000 solar viewing glasses after it sold out of them _ 17,000 pairs at $2 each _ last week.
Some online sites for viewing areas, with guidance on how best to observe the eclipse safely:
Fleischmann Planetarium at the University of Nevada, Reno: http://bit.ly/M5mV5b
Oregon Museum of Science and Industry: http://www.omsi.edu/node/743
Eclipse-watch party in Eugene, hosted by the Astronomical Society: http://www.eugeneastro.org/