Viewers in parts of Central America and the Caribbean should be able to catch a glimpse of an even slighter eclipse. The holiday light show takes place near the height of an 11-year cycle of sunspot activity on the sun. Astronomers caution observers to never look directly at the sun, including during a solar eclipse. The only difference is that human curiosity impels some people to stare directly at the sun during an eclipse and this can cause permanent damage to your eyesight. Espenak advises eclipse watchers to use specially designed solar filters on optical devices or even a simple pinhole camera, which allows users to view a projected image of the sun.
Eclipses can only happen when a new moon passes between the sun and Earth.
Observers can see the eclipse if the moon's shadow passes over them as it sweeps across the planet. The last solar eclipse on December 25 occurred in 1954. The next total solar eclipse will darken parts of South America and Africa on June 21, 2001. Another Christmas Day solar eclipse, a partial one, won't happen until 2307. Pages will open in a new browser window External sites are not endorsed by CNN Interactive.