Sunday, July 10

Aurora at Your Fingertips

"Seeing a great aurora ranks right up there with witnessing a total eclipse of the Sun. Auroraphiles travel thousands of miles and spend thousand dollars to join tours in frozen locales ringing the Arctic Circle in hopes of shivering under one of nature's grandest spectacles. The rest of us wait it out, hoping the next big aurora will find us neither asleep nor staring up at clouds. To anticipate the next great display, you'll need a forecast and three data points: the Kp index, a measure of the degree of disturbance in Earth's magnetic field; the Bz, or direction of the solar magnetic field in the vicinity of Earth, and a visual forecast model that shows the extent of the auroral oval. ..."
Sky and Telescope
W - Aurora (Video)