Stonehenge may be a simple calculator for predicting eclipses. Analysis by astronomers shows how prehistoric people could track the movement of the Sun and Moon, as well as the more complex cycle of the orbit of the Moon.



One ancient eclipse caused two armies to lay down their arms and make peace on the spot. In another time, a Greek navy got spooked by a lunar eclipse and paused their advance ... and the delay cost them a key battle victory!

Solar eclipses have perplexed both kings and common folk alike. Poets have waxed eloquently about the awe they feel when the Sun goes dark. Columbus even used an eclipse trick to convince Jamaican natives to help him.

If you're in the path and blessed with clear skies, you'll experience an unforgettable vision of the corona, the delicate halo of light that is always present surrounding the Sun, but visible only during a total solar eclipse.

It's the lunar nodes—two invisible points in space in the orbit of the Moon—that control the timing of eclipses. Early observers named them the head and the tail of the dragon, a key element of eclipse symbolism.

The speed and width of the Moon's shadow determine the duration of the total eclipse for a given location. To get more viewing time with the corona, select a site closer to the centerline of the path of totality.

The book lays out a complete guide to planning your own "eclipse expedition" to the path of totality. Equipment needed (very little). Guidance on selecting a great viewing site. Viewing tips.

For the partial phases of the event, don't look directly at the Sun; you must use eclipse glasses or a pinhole projector. But, during the few minutes of totality, remove your glasses and look directly at the spectacle of the corona.

Don't be surprised if you get hooked on chasing total solar eclipses. The next U.S. events occur in 2044 and 2045. But in 2027 you can travel to the Mediterranean, Egypt, or Saudi Arabia to experience up to 6 minutes of totality.