'Eclipse chasers' pay up to $10,000 to fly into the moon's shadow in chartered jets - here's what it's like

For the first time in nearly 100 years, the shadow of a total solar eclipse is going to sweep across the United States.

The umbra - the darkest shadow cast by the moon blocking the sun - will appear in the Pacific Ocean and slice through 12 US states on Monday, August 21.

Starting around 10 a.m. PDT, parts of western Oregon will go dark in a condition called totality as the umbra travels east. The elliptical shadow will make its way to Idaho Falls by 11:33 MDT, hit Kansas City at 1 p.m. CDT, and begin to pass over Charleston, South Carolina, by about 2:45 p.m. EDT.

Although some eclipse fans spend years preparing for the event, totality lasts less than three minutes - so all it takes is one stray cloud to obscure the magic moment.

That's why some people pay thousands of dollars to fly in chartered jets and pursue the moon's shadow. In addition to beating the odds of bad weather, such hardcore "eclipse chasers" can extend their length of time in the umbra, sometimes by several minutes.

I was lucky enough to ride an eclipse-chasing flight on August 1, 2008. Here's what the experience was like.