'Brocken Spectre' enchants couple atop foggy mountain peak

It's not easy to create your own optical illusion, but mountain climbers and hikers who have ever been out and about on a sunny and foggy day did just that, creating what's known as a "Brocken Spectre."

Radka Chapin and her husband got to see the amazing sight while they were up at Tamanos Mountain east of Mount Rainier on Saturday.

"We got treated to a spectacular light show with Brocken Spectre," she said. "We spent several hours on the summit! We tried to leave several times but then the Spectre would start showing again and it was so magnificent, we had to stay and watch it. We ended up hiking out with headlamps :) "

The effect, which projects your long shadow on top of a rainbow halo, requires sunshine, a person on a peak or at least someplace where they are higher than the horizon, and a fog or mist layer below. The specte is always shown exactly opposite from the sun, which is why if the sun is above the horizon, you have to be able to see the effect below your horizon, like, on top of a mountain. (The effect can be replicated on a flat surface if the sun is low on the horizon)

The shadow surrounded by the circular rainbow halo is caused as the light bends around you and your shadow is projected onto the fog/mist layer below. Much like where you see a rainbow positioned is unique to your eye, the spectre would also drift as your eye moves.

The great site Atmospheric Optics has a bit more technical explanations on Brocken Spectre and their related effect, "the glory". You can also see a similar effect if you've ever had a window seat on a plane on the shadow side of the fuselage -- the plane will cast a similar rainbow-halo shadow on the clouds below.

"I have wanted to see the Spectre for years and finally got lucky!" Chapin said.