Figure 3-11: R I V U X G

The Geometry of a Total Solar Eclipse During a total solar eclipse, the tip of the Moon’s umbra reaches Earth’s surface. As Earth and the Moon move along their orbits, this tip traces an eclipse path across Earth’s surface. People within the eclipse path see a total solar eclipse as the tip moves over them. Anyone within the penumbra sees only a partial eclipse. The inset photograph was taken from the Mir space station during the August 11, 1999, total solar eclipse (the same eclipse shown in Figure 3-10). The tip of the umbra appears as a black spot on Earth’s surface. At the time the photograph was taken, this spot was 105 km (65 mi) wide and was crossing the cloud-covered English Channel at 3000 km/h (1900 mi/h).

(Photograph by Jean-Pierre Haigneré, Centre National d’Etudes Spatiales, France/GSFS/NASA)