FRED ESPENAK has trained his eyes to the stars ever since he saw his first solar eclipse.
Intellectually, the Goddard Space Flight Center astrophysicist is well equipped to understand the motions of the heavens. But, "emotionally, it's hard to get a grip," he says. "You are witnessing the clockwork of the heavens, so to speak. It is no longer a purely academic, abstract notion. It is brought directly into your consciousness; you can see the moon shadow sweeping across the earth.
"It's almost as though somebody has a hand on a huge light dimmer switch," says Espenak, a Bowie resident, of the sun and the moon's dance, which has transfixed humanity throughout history.
Espenak has logged 10 total eclipses around the world, and authored the "Fifty Year Canon of Solar Eclipses: 1986-2035," a guide that tracks the narrow path of eclipse totality for 50 years. Undoubtedly, his book is a handy reference for the multitudes of eclipse chasers who conjoin for heavenly conjunctions whenever and wherever they occur -- usually in remote crannies of the globe.
Thursday, thousands of eclipse groupies, many of whom booked their trips years ago, will gather at Baja California and the island of Hawaii to watch this week's celestial pas de deux. For those who keep meticulous records of time spent in the moon's shadow it will be a bonanza. At 6 minutes, 58 seconds, this eclipse will be the longest in 18 years and the last total solar eclipse visible from the United States until Aug. 21, 2017.
About eclipses, Espenak waxes unabashedly poetic. As the sun takes refuge behind the moon, he says, it becomes "dim enough to see the sun's hairline crescent. It's extremely thin, but very bright. The horns of the crescent start narrowing and zippering inward to form brilliant diamonds.
"At the same time, the sun's corona starts becoming visible. It is ringed with dazzling diamonds, and when the diamonds are snuffed out in a couple more seconds, then the total eclipse has begun. Suddenly you look around, and you can see bright planets, it looks like a sunset surrounding the horizon. You look up at the sky to where the sun is and see the black disc of the moon, silhouetted by the corona. It has so much detail and is such a beautiful sight, that I've seen people break down and cry."
Espenak, of course, will be among those addicted to the perfect alignment of the moon and the sun who will witness the total eclipse. He is leading a flock of laymen eclipse chasers to the Baja. Last July, Espenak intercepted the moon's shadow in an aircraft over Finland. In 1984, he voyaged 12 hours into the Coral Sea off the coast of New Caledonia to watch a two-minute eclipse, only to turn around and make the 12-hour trip back.
Eclipse chasers cut across a galaxy of humanity. Scientists, laymen, New Agers, the young and the old all gravitate to the primitive pull of an eclipse, and the fears and thrills it instills.
"In some sense seeing my first eclipse is one thing that really made up my mind to go into astronomy," Espenak says.
"It was March 7, 1970, the last major eclipse visible from the East Coast of the United States. I was in high school, and I thought this was so rare, I figured it was my one chance in a lifetime to see one of these things," says Espenak, 39. "I begged my parents to let me drive 600 miles to get into the eclipse path" that led from Virginia Beach through Florida.
On the beach, Espenak witnessed a spectacle that activated a caldron of cosmic, atavistic, poetic, unsettling emotions. It "really strikes your senses. It's so unusual, and so different than anything you experience in everyday life," he says.
Mike Potter is another who can not escape the lure of a total eclipse. "It's an emotional high that you can't reproduce," says the senior science data analyst at the Space Telescope Science Institute in Baltimore. The upcoming eclipse will be his fifth.
"You get a real feeling for how it could be for people in past times [who saw eclipses as mystical events.] Even though you know exactly what's going on, by the same token your knees are knocking, you have cold sweaty hands. You drop things, you're nervous," Potter says.
Potter will be on a cruise poised to steam toward an optimal vantage point, should clouds threaten to obscure the eclipse off the Baja. His most memorable eclipse so far took place in 1972 on the Gaspe Peninsula in Quebec, where tens of thousands of people had gathered. "Little by little, it got quieter and quieter. By the time totality reached us, there was dead silence. Not even the insects were making sounds," Potter remembers.