Like many amateur eclipse chasers, I allow a solar phenomenon to lure me to improbable corners of the world. I even have a tracking map tacked on my wall, showing a decade of eclipses.
On March 29 I will be watching another cosmic pas de deux, much as I did near Lyndhurst, Australia, on Dec. 4, 2002.
Then, our vintage tour bus roared across the dusty, roadless plain, clouds of silky dust billowing in its wake. Twenty-five miles from a remote settlement of just a dozen inhabitants we pulled to a stop near the edge of a dry lake. About 50 dedicated chasers climbed out of the bus and began setting up global positioning system equipment, tripods, and cameras.
We weren't in Australia's scorching outback by accident. We had traveled from as far away as England to witness 26 seconds -- almost 27 -- of a total solar eclipse.
The improbable site was chosen for being on the ''center line" of the eclipse's 22-mile-wide path, and for its good weather prospects. Tens of thousands of people had journeyed to other points along the track to watch the light go out. A four-day, 80,000-watt techno music rave just outside Lyndhurst had attracted more than 5,000 revelers.
Anticipation built during the hour leading up to totality -- the point when the moon would completely obscure the sun. The light dimmed gradually, as though one scrim after another was being applied to the scene. Only through Mylar eye filters could we safely observe the moon slinking in front of the sun. Meanwhile, the shadow created by this celestial alignment -- the umbra -- was racing across the Indian Ocean toward us, at a speed of 14,000 miles per hour.
A few minutes before totality, the illumination started to darken dramatically and shadows became crisper. As the moon moved to cloak the sun, the excitement was audible, capped by whoops and cheers when the sun suddenly disappeared and an exquisite white halo burst from the perimeter of the moon.
We took off our cardboard glasses and witnessed an alien spectacle. The sky above was a deep, dark blue, and the horizon in all directions glowed like a 360-degree sunset. The air had cooled, and with color drained from the landscape, the earth suddenly felt lifeless. A woman standing near me stared at the phenomenon with her mouth agape, a teardrop caressing her cheek.
And then, after not even half a minute, totality was over and it was time to shield our eyes again.
Was it worth thousands of dollars and days of travel to get to this place? By itself, not quite. But packaged with an independent exploration of South Australia's wine country and opal mines, the event was the climax of a terrific expedition.
And I know where I'll be on March 29. So does Fred Espenak, an astrophysicist with the Goddard Space Flight Center of NASA in Greenbelt, Md., who does the calculations to forecast eclipses. Jay Anderson, a retired meteorologist with Environment Canada, assesses probable weather conditions. Together they compile Web documents that have become vital resources for hundreds of tour operators around the globe that cater to eclipse aficionados. For the March eclipse, I will be in Turkey, Espenak in Libya, and Anderson in Egypt.
I skipped the last two total solar eclipses, in 2003 and earlier this year. They were observable only from Antarctica and from the middle of the Pacific Ocean. This next eclipse is calculated to start at dawn along the coast of Brazil and then sprint across the Atlantic Ocean toward Africa. The umbra -- 115 miles wide at its broadest -- is expected to come ashore in Ghana and head northeast into the Sahara, crossing Nigeria, Niger, Chad, Libya, and Egypt before traversing the Mediterranean. The shadow then should course through Turkey, Georgia, Russia, and Kazakhstan, dissolving into dusk at the border of Mongolia.
At its maximum, in the Sahara, the eclipse is slated to last four minutes, seven seconds. As with any eclipse, not all points along the route are created equal. There are several considerations for choosing a viewing site, starting with weather prospects.
''There are no measurements for sunshine in the middle of the Sahara," Anderson says, ''but I'm estimating close to 80 percent sunshine in Bilma, Niger, and Jalu, Libya," the most accessible observation sites along the path through the desert.
After Niger and Libya, his next pick is Salum, Egypt, where sunshine statistics are about 75 percent, but Anderson cautions that March and April are also peak season for occasional dust storms.
Although total solar eclipses occur every 19 months on average, one won't be visible in North America until 2017. The next eclipse will visit Asia Aug. 1, 2008, a week before the opening of the Beijing Summer Olympic Games.
Hmmm . . . maybe that track will cross a scenic stretch of the Great Wall.
San Diego-based freelance writer David Swanson has seen solar eclipses in 1998, 1999, and 2002.