The Geometry of a Total Solar Eclipse

During a total solar eclipse, the tip of the Moon’s umbra traces an eclipse path across Earth’s surface. People inside the eclipse path see a total solar eclipse, whereas people inside the penumbra see only a partial eclipse. The photograph in this figure shows the Moon’s shadow on Earth. It was  taken from the Mir space station  during the August 11, 1999, total solar  eclipse. The Moon’s umbra appears as the very dark spot on the eastern coast of the United States. The umbra is surrounded by the penumbra. (Jean-Pierre Haigneré, Centre National d’Etudes Spatiales